Redundant expressions in AMDGPUGenAsmMatcher.inc

Hi!

Clang-tidy misc-redundant-expression reports a lot of redundant
expressions in AMDGPUGenAsmMatcher.inc. For example:

lib/Target/AMDGPU/AMDGPUGenAsmMatcher.inc:32253:17: warning: both side
of operator are equivalent [misc-redundant-expression]
  { Feature_isVI|Feature_isVI, 18275 /* v_xor_b32 */,
MCK_ImmSDWADstUnused, 32 /* 5 */ },

I think will be good idea if somebody who knows AMDGPU and table
generation specific will look onto this issue.

Eugene.