drm/sti: fix atomic_disable check

When a drm_plane is being disabled, its ->crtc member is set to NULL
before the .atomic_disable() func is called.
To get the crtc of the plane, read old_state->crtc instead of
drm_plane->crtc

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Acked-by: Vincent Abriou <vincent.abriou@st.com>
diff --git a/drivers/gpu/drm/sti/sti_cursor.c b/drivers/gpu/drm/sti/sti_cursor.c
index 651f231..cca75bd 100644
--- a/drivers/gpu/drm/sti/sti_cursor.c
+++ b/drivers/gpu/drm/sti/sti_cursor.c
@@ -309,15 +309,15 @@
 {
 	struct sti_plane *plane = to_sti_plane(drm_plane);
 
-	if (!drm_plane->crtc) {
+	if (!oldstate->crtc) {
 		DRM_DEBUG_DRIVER("drm plane:%d not enabled\n",
 				 drm_plane->base.id);
 		return;
 	}
 
 	DRM_DEBUG_DRIVER("CRTC:%d (%s) drm plane:%d (%s)\n",
-			 drm_plane->crtc->base.id,
-			 sti_mixer_to_str(to_sti_mixer(drm_plane->crtc)),
+			 oldstate->crtc->base.id,
+			 sti_mixer_to_str(to_sti_mixer(oldstate->crtc)),
 			 drm_plane->base.id, sti_plane_to_str(plane));
 
 	plane->status = STI_PLANE_DISABLING;
diff --git a/drivers/gpu/drm/sti/sti_gdp.c b/drivers/gpu/drm/sti/sti_gdp.c
index 1d5ebe4..083c0ac 100644
--- a/drivers/gpu/drm/sti/sti_gdp.c
+++ b/drivers/gpu/drm/sti/sti_gdp.c
@@ -846,15 +846,15 @@
 {
 	struct sti_plane *plane = to_sti_plane(drm_plane);
 
-	if (!drm_plane->crtc) {
+	if (!oldstate->crtc) {
 		DRM_DEBUG_DRIVER("drm plane:%d not enabled\n",
 				 drm_plane->base.id);
 		return;
 	}
 
 	DRM_DEBUG_DRIVER("CRTC:%d (%s) drm plane:%d (%s)\n",
-			 drm_plane->crtc->base.id,
-			 sti_mixer_to_str(to_sti_mixer(drm_plane->crtc)),
+			 oldstate->crtc->base.id,
+			 sti_mixer_to_str(to_sti_mixer(oldstate->crtc)),
 			 drm_plane->base.id, sti_plane_to_str(plane));
 
 	plane->status = STI_PLANE_DISABLING;
diff --git a/drivers/gpu/drm/sti/sti_hqvdp.c b/drivers/gpu/drm/sti/sti_hqvdp.c
index c6b25f4..d9ff79e 100644
--- a/drivers/gpu/drm/sti/sti_hqvdp.c
+++ b/drivers/gpu/drm/sti/sti_hqvdp.c
@@ -1215,15 +1215,15 @@
 {
 	struct sti_plane *plane = to_sti_plane(drm_plane);
 
-	if (!drm_plane->crtc) {
+	if (!oldstate->crtc) {
 		DRM_DEBUG_DRIVER("drm plane:%d not enabled\n",
 				 drm_plane->base.id);
 		return;
 	}
 
 	DRM_DEBUG_DRIVER("CRTC:%d (%s) drm plane:%d (%s)\n",
-			 drm_plane->crtc->base.id,
-			 sti_mixer_to_str(to_sti_mixer(drm_plane->crtc)),
+			 oldstate->crtc->base.id,
+			 sti_mixer_to_str(to_sti_mixer(oldstate->crtc)),
 			 drm_plane->base.id, sti_plane_to_str(plane));
 
 	plane->status = STI_PLANE_DISABLING;