Implementing a lock for selecting and accessing shader engines and arrays.
This lock will make sure that radeon and amdkfd are not colliding when
accessing shader engines and arrays with GRBM_GFX_INDEX register.
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NOded Gabbay <oded.gabbay@amd.com>