drm/amdgpu: use kiq to do invalidate tlb

To avoid the tlb flush not interrupted by world switch, use kiq and one
command to do tlb invalidate.

v2:
Refine the invalidate lock position.

Signed-off-by: Emily Deng <Emily.Deng@amd.com>
Reviewed-and-Tested-by: Rex Zhu <Rex.Zhu@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>