drm/i915: gt-fy sseu debugfs

drm/i915: gt-fy sseu debugfs

Ahead of moving the sseu debugfs logic under gt/, update the functions
to use intel_gt where possible to make the move cleaner.

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200708003952.21831-9-daniele.ceraolospurio@intel.com