Add FMF to vector ops for phi

Summary: Small amendment to handle vector cases for D67564.

Reviewers: spatel, eli.friedman, hfinkel, cameron.mcinally, arsenm, jmolloy, bogner

Reviewed By: cameron.mcinally, bogner

Subscribers: llvm-commits, efriedma, reames, bogner, wdng

Differential Revision: https://reviews.llvm.org/D68748

llvm-svn: 374794