drm/amdgpu: enable compute/gfx usermode queue

This patch does the necessary changes required to
enable compute workload support using the existing
usermode queues infrastructure.

V9:  Patch introduced
V10: Add custom IP specific mqd strcuture for compute (Alex)
V11: Rename drm_amdgpu_userq_mqd_compute_gfx_v11 to
     drm_amdgpu_userq_mqd_compute_gfx11 (Marek)

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian Koenig <christian.koenig@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Arvind Yadav <arvind.yadav@amd.com>
Signed-off-by: Shashank Sharma <shashank.sharma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>