drm/i915: Drop explicit plane restoration during resume

We already restore planes during the modeset operation, so no need to do
another loop over the planes and try to restore them again.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>