drm/i915: Eliminate passing dev+dev_priv to {snb,ilk}_gt_irq_handler()

It looks silly to pass both dev and dev_priv to the snb/ilk gt irq
handlers. Just pass dev_priv.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1460571598-24452-12-git-send-email-ville.syrjala@linux.intel.com


Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>