[X86] Utilize SelectionDAG::getSelect(). NFC.

Replace SelectionDAG::getNode(ISD::SELECT, ...)
and SelectionDAG::getNode(ISD::VSELECT, ...)
with SelectionDAG::getSelect(...)
Saves a few lines of code and in some cases saves the need to explicitly
check the type of the desired node.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303024 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed