Add missing check

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/aes.c b/library/aes.c
index 888ac0f..1e1039b 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -41,7 +41,7 @@
 #endif
 
 #if defined(__amd64__) || defined(__x86_64__) || \
-    defined(_M_X64) || defined(_M_AMD64)
+    ((defined(_M_X64) || defined(_M_AMD64)) && !defined(_M_ARM64EC))
 #if !defined(MBEDTLS_AESNI_C) && defined(MBEDTLS_AES_USE_HARDWARE_ONLY)
 #error "MBEDTLS_AES_USE_HARDWARE_ONLY defined, but not all prerequisites"
 #endif