Replace MBEDTLS_ERR_OID_NOT_FOUND with MBEDTLS_ERR_X509_UNKNOWN_OID

Replace the non-X.509-named error code `MBEDTLS_ERR_OID_NOT_FOUND` with
`MBEDTLS_ERR_X509_UNKNOWN_OID`, which already exists and is currently not
used for anything.

Public functions in X.509 propagate this error code, so it needs to have a
public name.

Remove the definition of `MBEDTLS_ERR_OID_NOT_FOUND` in `x509_oid.h`, then

```
git grep -l MBEDTLS_ERR_OID_NOT_FOUND | xargs perl -i -pe 's/\bMBEDTLS_ERR_OID_NOT_FOUND\b/MBEDTLS_ERR_X509_UNKNOWN_OID/g'
```

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/suites/test_suite_x509parse.data b/tests/suites/test_suite_x509parse.data
index 6a04ff0..c7c465b 100644
--- a/tests/suites/test_suite_x509parse.data
+++ b/tests/suites/test_suite_x509parse.data
@@ -1386,11 +1386,11 @@
 
 X509 CRT ASN1 (TBS, inv AlgID, OID empty)
 depends_on:PSA_WANT_ALG_SHA_256:MBEDTLS_RSA_C
-x509parse_crt:"307f3075a0030201008204deadbeef30020600300c310a30080600130454657374301c170c303930313031303030303030170c303931323331323335393539300c310a30080600130454657374302a300d06092A864886F70D010101050003190030160210ffffffffffffffffffffffffffffffff0202ffff30020600030200ff":"":MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG, MBEDTLS_ERR_OID_NOT_FOUND)
+x509parse_crt:"307f3075a0030201008204deadbeef30020600300c310a30080600130454657374301c170c303930313031303030303030170c303931323331323335393539300c310a30080600130454657374302a300d06092A864886F70D010101050003190030160210ffffffffffffffffffffffffffffffff0202ffff30020600030200ff":"":MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG, MBEDTLS_ERR_X509_UNKNOWN_OID)
 
 X509 CRT ASN1 (TBS, inv AlgID, OID unknown)
 depends_on:PSA_WANT_ALG_SHA_256:MBEDTLS_RSA_C
-x509parse_crt:"3081873079a0030201008204deadbeef30060604deadbeef300c310a30080600130454657374301c170c303930313031303030303030170c303931323331323335393539300c310a30080600130454657374302a300d06092A864886F70D010101050003190030160210ffffffffffffffffffffffffffffffff0202ffff30060604deadbeef030200ff":"":MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG, MBEDTLS_ERR_OID_NOT_FOUND)
+x509parse_crt:"3081873079a0030201008204deadbeef30060604deadbeef300c310a30080600130454657374301c170c303930313031303030303030170c303931323331323335393539300c310a30080600130454657374302a300d06092A864886F70D010101050003190030160210ffffffffffffffffffffffffffffffff0202ffff30060604deadbeef030200ff":"":MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG, MBEDTLS_ERR_X509_UNKNOWN_OID)
 
 X509 CRT ASN1 (TBS, inv AlgID, param inv length encoding)
 depends_on:PSA_WANT_ALG_SHA_256:MBEDTLS_RSA_C
@@ -2845,7 +2845,7 @@
 x509_parse_rsassa_pss_params:"a00f300d06096086480165030402013000":MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE:MBEDTLS_MD_SHA256:MBEDTLS_MD_SHA1:20:MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_ALG, MBEDTLS_ERR_ASN1_INVALID_DATA)
 
 X509 RSASSA-PSS parameters ASN1 (HashAlg unknown OID)
-x509_parse_rsassa_pss_params:"a00d300b06096086480165030402ff":MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE:MBEDTLS_MD_SHA256:MBEDTLS_MD_SHA1:20:MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_ALG, MBEDTLS_ERR_OID_NOT_FOUND)
+x509_parse_rsassa_pss_params:"a00d300b06096086480165030402ff":MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE:MBEDTLS_MD_SHA256:MBEDTLS_MD_SHA1:20:MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_ALG, MBEDTLS_ERR_X509_UNKNOWN_OID)
 
 X509 RSASSA-PSS parameters ASN1 (good, MGAlg = MGF1-SHA256)
 depends_on:MBEDTLS_RSA_C:PSA_WANT_ALG_SHA_256
@@ -2866,7 +2866,7 @@
 x509_parse_rsassa_pss_params:"a11a301906092a864886f70d010108300b0609608648016503040201":MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE:MBEDTLS_MD_SHA1:MBEDTLS_MD_SHA256:20:MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_ALG, MBEDTLS_ERR_ASN1_OUT_OF_DATA)
 
 X509 RSASSA-PSS parameters ASN1 (MGAlg OID != MGF1)
-x509_parse_rsassa_pss_params:"a11a301806092a864886f70d010109300b0609608648016503040201":MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE:MBEDTLS_MD_SHA1:MBEDTLS_MD_SHA256:20:MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE, MBEDTLS_ERR_OID_NOT_FOUND)
+x509_parse_rsassa_pss_params:"a11a301806092a864886f70d010109300b0609608648016503040201":MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE:MBEDTLS_MD_SHA1:MBEDTLS_MD_SHA256:20:MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE, MBEDTLS_ERR_X509_UNKNOWN_OID)
 
 X509 RSASSA-PSS parameters ASN1 (MGAlg.params wrong tag)
 x509_parse_rsassa_pss_params:"a11a301806092a864886f70d010108310b0609608648016503040201":MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE:MBEDTLS_MD_SHA1:MBEDTLS_MD_SHA256:20:MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_ALG, MBEDTLS_ERR_ASN1_UNEXPECTED_TAG)
@@ -2881,7 +2881,7 @@
 x509_parse_rsassa_pss_params:"a11a301806092a864886f70d010108300b0709608648016503040201":MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE:MBEDTLS_MD_SHA1:MBEDTLS_MD_SHA256:20:MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_ALG, MBEDTLS_ERR_ASN1_UNEXPECTED_TAG)
 
 X509 RSASSA-PSS parameters ASN1 (MGAlg.params.alg unknown OID)
-x509_parse_rsassa_pss_params:"a11a301806092a864886f70d010108300b06096086480165030402ff":MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE:MBEDTLS_MD_SHA1:MBEDTLS_MD_SHA256:20:MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_ALG, MBEDTLS_ERR_OID_NOT_FOUND)
+x509_parse_rsassa_pss_params:"a11a301806092a864886f70d010108300b06096086480165030402ff":MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE:MBEDTLS_MD_SHA1:MBEDTLS_MD_SHA256:20:MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_ALG, MBEDTLS_ERR_X509_UNKNOWN_OID)
 
 X509 RSASSA-PSS parameters ASN1 (MGAlg.params.params NULL)
 depends_on:MBEDTLS_RSA_C:PSA_WANT_ALG_SHA_256