updated patch for the ARM fused multiply add/sub

updated patch for the ARM fused multiply add/sub

In this update:
- I assumed neon2 does not imply vfpv4, but neon and vfpv4 imply neon2.
- I kept setting .fpu=neon-vfpv4 code attribute because that is what the
assembler understands.

Patch by Ana Pazos <apazos@codeaurora.org>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152036 91177308-0d34-0410-b5e6-96231b3b80d8