drm/i915: Convert resume to atomic.

Instead of all the ad-hoc updating, duplicate the old state first
before reading out the hw state, then restore it.

intel_display_resume is a new function that duplicates the sw state,
then reads out the hw state, and commits the old state.

intel_display_setup_hw_state now only reads out the atomic state.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90396
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 937e821..cb634f4 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -473,7 +473,7 @@
 	 */
 	if (!HAS_PCH_SPLIT(dev)) {
 		drm_modeset_lock_all(dev);
-		intel_modeset_setup_hw_state(dev, true);
+		intel_display_resume(dev);
 		drm_modeset_unlock_all(dev);
 	}