drm/amdgpu: convert gfx.kiq to array type (v3)

v1: more kiq instances are a available in SOC (Le)
v2: squash commits to avoid breaking the build (Le)
v3: make the conversion for gfx/mec 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>