[AMDGPU] Remove deprecated V_MUL_LO_I32 from GFX10

It was removed in GFX10 GPUs, but LLVM could
generate it.

Reviewed By: rampitec, arsenm

Differential Revision: https://reviews.llvm.org/D94020

Change-Id: Id1c716d71313edcfb768b2b175a6789ef9b01f3c