Replace hash_info macro with MD macro

Now the MD macro also accounts for PSA-only hashes.

Just a search-and-replace, plus manually removing the definition in
hash_info.h.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/library/ssl_tls12_client.c b/library/ssl_tls12_client.c
index b875fac..df4c003 100644
--- a/library/ssl_tls12_client.c
+++ b/library/ssl_tls12_client.c
@@ -2291,7 +2291,7 @@
 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
     if (mbedtls_ssl_ciphersuite_uses_server_signature(ciphersuite_info)) {
         size_t sig_len, hashlen;
-        unsigned char hash[MBEDTLS_HASH_MAX_SIZE];
+        unsigned char hash[MBEDTLS_MD_MAX_SIZE];
 
         mbedtls_md_type_t md_alg = MBEDTLS_MD_NONE;
         mbedtls_pk_type_t pk_alg = MBEDTLS_PK_NONE;