[ARM] GlobalISel: Support G_(S|U)REM for s8 and s16

Widen to s32, and then do whatever Lowering/Custom/Libcall action the
subtarget wants.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@308285 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed