add hardware only check for padlock

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/aes.c b/library/aes.c
index b99a8db..968cd31 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -52,7 +52,8 @@
 #error "MBEDTLS_AES_USE_HARDWARE_ONLY defined, but not all prerequisites"
 #endif
 
-#if defined(MBEDTLS_PADLOCK_C) && !defined(MBEDTLS_HAVE_ASM)
+#if defined(MBEDTLS_PADLOCK_C) && \
+    (!defined(MBEDTLS_HAVE_ASM) || defined(MBEDTLS_AES_USE_HARDWARE_ONLY))
 #error "MBEDTLS_PADLOCK_C defined, but not all prerequisites"
 #endif
 #endif