Make the alternative aes optional

Have the alternative aes undefined by default,
in order not to break backwards compatability.
`MBEDTLS_CTR_DRBG_USE_128_BIT_KEY` remains defined for better usability.

Author: Ron Eldor

features/cryptocell/FEATURE_CRYPTOCELL310/mbedtls_device.h

@@ -22,7 +22,7 @@
 #define __MBEDTLS_DEVICE__
 
 #define MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT
-#define MBEDTLS_AES_ALT
+//#define MBEDTLS_AES_ALT
 #define MBEDTLS_CTR_DRBG_USE_128_BIT_KEY
 #define MBEDTLS_SHA1_ALT
 #define MBEDTLS_SHA256_ALT