[X86] Make sure we don't combine (fneg (fma X, Y, Z)) to a target specific node when there are no FMA instructions.

This would cause a 'cannot select' error at isel when we should have emitted a lib call and an xor.

Fixes PR36553.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@326393 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed