[ARM] Replace processor check with feature

Add new feature, `FeatureUseWideStrideVFP`, that replaces the need for a
processor check.  Otherwise, NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339354 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed