Make naming more consistent

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/cipher_wrap.c b/library/cipher_wrap.c
index 890be3c..6ab2f5f 100644
--- a/library/cipher_wrap.c
+++ b/library/cipher_wrap.c
@@ -123,7 +123,7 @@
     MBEDTLS_CIPHER_BASE_INDEX_XTS_AES,
 #endif
     /* Prevent compile failure due to empty enum */
-    MBEDTLS_PREVENT_EMPTY_ENUM
+    MBEDTLS_CIPHER_BASE_PREVENT_EMPTY_ENUM
 };
 
 #if defined(MBEDTLS_GCM_C)