drm/atomic: Add new iterators over all state, v3.

Add for_each_(old)(new)_(plane,connector,crtc)_in_state iterators to
replace the old for_each_xxx_in_state ones. This is useful for >1 flip
depth and getting rid of all xxx->state dereferences.

This requires extra fixups done when committing a state after
duplicating, which in general isn't valid but is used by suspend/resume.
To handle these, introduce drm_atomic_helper_commit_duplicated_state
which performs those fixups before checking & committing the state.

Changes since v1:
- Remove nonblock parameter for commit_duplicated_state.
Changes since v2:
- Use commit_duplicated_state for i915 load detection.
- Add WARN_ON(old_state != obj->state) before swapping.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1484559464-27107-2-git-send-email-maarten.lankhorst@linux.intel.com
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index c97588a..28f192a 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -275,6 +275,8 @@ drm_atomic_get_crtc_state(struct drm_atomic_state *state,
 		return ERR_PTR(-ENOMEM);
 
 	state->crtcs[index].state = crtc_state;
+	state->crtcs[index].old_state = crtc->state;
+	state->crtcs[index].new_state = crtc_state;
 	state->crtcs[index].ptr = crtc;
 	crtc_state->state = state;
 
@@ -689,6 +691,8 @@ drm_atomic_get_plane_state(struct drm_atomic_state *state,
 
 	state->planes[index].state = plane_state;
 	state->planes[index].ptr = plane;
+	state->planes[index].old_state = plane->state;
+	state->planes[index].new_state = plane_state;
 	plane_state->state = state;
 
 	DRM_DEBUG_ATOMIC("Added [PLANE:%d:%s] %p state to %p\n",
@@ -1028,6 +1032,8 @@ drm_atomic_get_connector_state(struct drm_atomic_state *state,
 
 	drm_connector_reference(connector);
 	state->connectors[index].state = connector_state;
+	state->connectors[index].old_state = connector->state;
+	state->connectors[index].new_state = connector_state;
 	state->connectors[index].ptr = connector;
 	connector_state->state = state;