Use memcmp instead of reinventing it

Signed-off-by: Thomas Daubney <thomas.daubney@arm.com>
diff --git a/programs/psa/psa_hash.c b/programs/psa/psa_hash.c
index f09b48c..a2e2731 100644
--- a/programs/psa/psa_hash.c
+++ b/programs/psa/psa_hash.c
@@ -134,13 +134,12 @@
         return EXIT_FAILURE;
     }
 
-    for (size_t j = 0; j < test_sha256_hash_len; j++) {
-        if (hash[j] != test_sha256_hash[j]) {
-            mbedtls_printf("One-shot hash operation gave the wrong result!\n\n");
-            psa_hash_abort(&hash_operation);
-            psa_hash_abort(&cloned_hash_operation);
-            return EXIT_FAILURE;
-        }
+    if (memcmp(hash, test_sha256_hash, test_sha256_hash_len) != 0)
+    {
+        mbedtls_printf("One-shot hash operation gave the wrong result!\n\n");
+        psa_hash_abort(&hash_operation);
+        psa_hash_abort(&cloned_hash_operation);
+        return EXIT_FAILURE;
     }
 
     mbedtls_printf("One-shot hash operation successful!\n\n");