psa: config: Add MBEDTLS_PSA_CRYPTO_SPM

We failed check-names.sh due to using a define which wasn't described or
defined anywhere. Even though we won't realistically enable
MBEDTLS_PSA_CRYPTO_SPM via the configuration system (and will do it from
PSA Crypto SPM tooling instead), add a description of the configuration to
config.h as good practice. Exclude MBEDTLS_PSA_CRYPTO_SPM from the "full"
configuration as well.
diff --git a/library/version_features.c b/library/version_features.c
index b77bf26..9917ec0 100644
--- a/library/version_features.c
+++ b/library/version_features.c
@@ -414,6 +414,9 @@
 #if defined(MBEDTLS_PKCS1_V21)
     "MBEDTLS_PKCS1_V21",
 #endif /* MBEDTLS_PKCS1_V21 */
+#if defined(MBEDTLS_PSA_CRYPTO_SPM)
+    "MBEDTLS_PSA_CRYPTO_SPM",
+#endif /* MBEDTLS_PSA_CRYPTO_SPM */
 #if defined(MBEDTLS_RSA_NO_CRT)
     "MBEDTLS_RSA_NO_CRT",
 #endif /* MBEDTLS_RSA_NO_CRT */