[X86] Adjust cost of FP_TO_UINT v4f64->v4i32 as well

Pretty obvious follow-on to r205159 to also handle conversion from double
besides float.

Fixes <rdar://problem/16373208>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205253 91177308-0d34-0410-b5e6-96231b3b80d8