[AMDGPU] gfx11 Image instructions

MC layer support for instructions in the MIMG encoding(Image
instructions).

Contributors:
Carl Ritson <carl.ritson@amd.com>

Patch 13/N for upstreaming of AMDGPU gfx11 architecture.

Depends on D125992

Reviewed By: rampitec, #amdgpu

Differential Revision: https://reviews.llvm.org/D126463