[ARM] FP16Pat and FullFP16Pat patterns. NFC.

Create and use FP16Pat FullFP16Pat helper patterns to make the difference
explicit.

Differential Revision: https://reviews.llvm.org/D42634


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@323640 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed