[DAGCombine] Use getSetCCResultType utility function

DAGCombine has a utility wrapper around TLI's getSetCCResultType; use it in the
one place in DAGCombine still directly calling the TLI function. NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246482 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed