Fully replace mbedtls_psa_safer_memcmp

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/psa_crypto_mac.c b/library/psa_crypto_mac.c
index 07f123e..2f2c51d 100644
--- a/library/psa_crypto_mac.c
+++ b/library/psa_crypto_mac.c
@@ -29,6 +29,7 @@
 #include <mbedtls/md.h>
 
 #include <mbedtls/error.h>
+#include "mbedtls/constant_time.h"
 #include <string.h>
 
 #if defined(MBEDTLS_PSA_BUILTIN_ALG_HMAC)
@@ -453,7 +454,7 @@
         goto cleanup;
     }
 
-    if (mbedtls_psa_safer_memcmp(mac, actual_mac, mac_length) != 0) {
+    if (mbedtls_ct_memcmp(mac, actual_mac, mac_length) != 0) {
         status = PSA_ERROR_INVALID_SIGNATURE;
     }