[ARM][AArch64] Correct __ARM_FEATURE_CRYPTO macro and crypto feature

This patch contains a couple of minor corrections to my previous
crypto patch:

Since both AArch32 and AArch64 are now correctly setting the aes and
sha2 features individually, it is not necessary to continue to check
the crypto feature when defining feature macros.

In the AArch32 driver, the feature vector is only modified when the
crypto feature is actually in the vector. If crypto is not present,
there is no need to split it and explicitly define crypto/sha2/aes.

Reviewed By: lenary

Differential Revision: https://reviews.llvm.org/D102406