[ARM] Fix NEON wrongly being enabled with soft-float when targeting armv8/Cortex-A53/A57.

This was caused by r200708 which enabled the crypto feature for these cores.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@201223 91177308-0d34-0410-b5e6-96231b3b80d8