drm/i915/gt: SPDX cleanup

Clean up the SPDX licence declarations to comply with checkpatch.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210122192913.4518-1-chris@chris-wilson.co.uk
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drm/i915: Extract GT powermanagement interrupt handling

i915_irq.c is large. It serves as the central dispatch and handler for
all of our device interrupts. Pull out the GT pm interrupt handling
(leaving the central dispatch) so that we can encapsulate the logic a
little better.

Based on a patch by Chris Wilson.

Signed-off-by: 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/20190811142801.2460-1-chris@chris-wilson.co.uk