[Sparc] Implement UMUL_LOHI and SMUL_LOHI instead of MULHS/MULHU/MUL.

This is what the instruction-set actually provides, and the default
expansions of the others into the lohi opcodes are good.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283381 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed