[AMDGPU] Refactor v_mac_{f16, f32} patterns into a class NFC

Differential Revision: https://reviews.llvm.org/D26711


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@287077 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed