drm/amdgpu: Fix KIQ hang on bare metal for device unbind/bind back v2.

Problem: When unbind and then bind back the device KIQ hangs on Vega
after mapping KCQs request.

Fix: Adding deinitialzie code from CAIL  during HW fini solves the
hang.

v2: use srbm_mutex around soc15_grbm_select()

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>