drm/i915/chv: Add Cherryview interrupt registers into debugfs
Make i915_gem_interrupt debugfs file functional on CHV.
FIXME: Extract helpers for gt/display blocks to shrink the function a
bit and avoid duplication between bdw/chv (and other similar cases for
upstream).
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>