Fix instances of old feature macros being used

sed -i -f md.sed include/mbedtls/ssl.h library/hmac_drbg.c programs/pkey/*.c programs/x509/*.c tests/scripts/generate_pkcs7_tests.py tests/suites/test_suite_random.data

Then manually revert programs/pkey/ecdsa.c as it's using a low-level
hash API.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/programs/x509/cert_req.c b/programs/x509/cert_req.c
index 5241438..01d09bc 100644
--- a/programs/x509/cert_req.c
+++ b/programs/x509/cert_req.c
@@ -22,13 +22,13 @@
 #include "mbedtls/platform.h"
 
 #if !defined(MBEDTLS_X509_CSR_WRITE_C) || !defined(MBEDTLS_FS_IO) ||  \
-    !defined(MBEDTLS_PK_PARSE_C) || !defined(MBEDTLS_SHA256_C) || \
+    !defined(MBEDTLS_PK_PARSE_C) || !defined(MBEDTLS_MD_CAN_SHA256) || \
     !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_CTR_DRBG_C) || \
     !defined(MBEDTLS_PEM_WRITE_C)
 int main(void)
 {
     mbedtls_printf("MBEDTLS_X509_CSR_WRITE_C and/or MBEDTLS_FS_IO and/or "
-                   "MBEDTLS_PK_PARSE_C and/or MBEDTLS_SHA256_C and/or "
+                   "MBEDTLS_PK_PARSE_C and/or MBEDTLS_MD_CAN_SHA256 and/or "
                    "MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C "
                    "not defined.\n");
     mbedtls_exit(0);