psa: Fix the size of hash buffers

Fix the size of hash buffers for PSA hash
operations.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 0d54ae9..5c27692 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -6967,7 +6967,7 @@
         goto exit;
     }
 
-    if( ( status = psa_hash_finish( &hash_operation, hash, MBEDTLS_MD_MAX_SIZE,
+    if( ( status = psa_hash_finish( &hash_operation, hash, PSA_HASH_MAX_SIZE,
                                     hashlen ) ) != PSA_SUCCESS )
     {
          MBEDTLS_SSL_DEBUG_RET( 1, "psa_hash_finish", status );