The new node provides access to the status of the GuC-specific loader;
also the scratch registers used for communication between the i915
driver and the GuC firmware.

v2:
    Changes to output formats per Chris Wilson's suggestions

v6:
    Rebased

Issue: VIZ-4884
Signed-off-by: NAlex Dai <yu.dai@intel.com>
Signed-off-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NTom O'Rourke <Tom.O'Rourke@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>