drm/amdgpu: add multi-xcc support to amdgpu_gfx interfaces (v4)

v1: Modify kiq_init/fini, mqd_sw_init/fini and
enable/disable_kcq to adapt to multi-die case.
Pass 0 as default to all asics with single xcc (Le)
v2: squash commits to avoid breaking the build (Le)
v3: unify naming style (Le)
v4: apply the changes to gc v11_0 (Hawking)

Signed-off-by: Le Ma <le.ma@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>