x86: NFC remove needless InstrCompiler cast

Summary: The casts from String to PatFrag weren't needed if we instead provided an SDNode. This fix was suggested by @pete in D11382.

Subscribers: pete, llvm-commits

Differential Revision: http://reviews.llvm.org/D11788

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244167 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed