drm/amdgpu: Add MES KIQ clear to tell RLC that KIQ is dequeued

drm/amdgpu: Add MES KIQ clear to tell RLC that KIQ is dequeued

[Why]
As MES KIQ is dequeued, tell RLC that KIQ is inactive

[How]
Clear the RLC_CP_SCHEDULERS Active bit which RLC checks KIQ status
In addition, driver can halt MES under SRIOV when unloading driver

v2:
Use scheduler0 mask to clear KIQ portion of RLC_CP_SCHEDULERS

Signed-off-by: Yifan Zha <Yifan.Zha@amd.com>
Reviewed-by: Horace Chen <horace.chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>