drm/amdgpu: add init support for GFX11 (v2)

Add initial support for GC version 11.  GC is
the graphics and compute block on the GPU.

v1: add initial gfx11 support (Wenhui)
v2: switch to new amdgpu_gfx_is_high_priority_compute_queue
    interface (Hawking)
v3: fix num_mec (Alex)

Signed-off-by: Wenhui Sheng <Wenhui.Sheng@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>