drm/amdgpu: Rework MES initialization on GFX 12.1

drm/amdgpu: Rework MES initialization on GFX 12.1

Currently, only SPX mode works on GFX 12.1. This patch reworks
the MES initialization to get other non-SPX modes working. For example,
for CPX mode, coop_enable bit needs to be set to 0. The shared command
buffer initialization is also not needed in CPX mode.
The shared command buffer initialization needs further improvements which
will be handled in later patches.

Signed-off-by: Mukul Joshi <mukul.joshi@amd.com>
Reviewed-by: Alex Sierra <alex.sierra@amd.com>
Reviewed-by: Michael Chen <michael.chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>