SelectionDAG: Don't use MVT::Other to determine legality of ISD::SELECT_CC

SelectionDAG: Don't use MVT::Other to determine legality of ISD::SELECT_CC

The SelectionDAG bad a special case for ISD::SELECT_CC, where it would
allow targets to specify:

setOperationAction(ISD::SELECT_CC, MVT::Other, Expand);

to indicate that they wanted to expand ISD::SELECT_CC for all types.
This wasn't applied correctly everywhere, and it makes writing new
DAG patterns with ISD::SELECT_CC difficult.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210541 91177308-0d34-0410-b5e6-96231b3b80d8