drm: sti: convert driver to atomic modeset

v1: This patch does the minimum to make sti driver use atomic helpers.
No big bang, only adapt some functions to new call order.

v2: Use dpms and page flip atomic helpers

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
diff --git a/drivers/gpu/drm/sti/sti_dvo.c b/drivers/gpu/drm/sti/sti_dvo.c
index aeb5070..a9b678a 100644
--- a/drivers/gpu/drm/sti/sti_dvo.c
+++ b/drivers/gpu/drm/sti/sti_dvo.c
@@ -11,6 +11,7 @@
 #include <linux/platform_device.h>
 
 #include <drm/drmP.h>
+#include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_panel.h>
 
@@ -364,10 +365,13 @@
 }
 
 static struct drm_connector_funcs sti_dvo_connector_funcs = {
-	.dpms = drm_helper_connector_dpms,
+	.dpms = drm_atomic_helper_connector_dpms,
 	.fill_modes = drm_helper_probe_single_connector_modes,
 	.detect = sti_dvo_connector_detect,
 	.destroy = sti_dvo_connector_destroy,
+	.reset = drm_atomic_helper_connector_reset,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 };
 
 static struct drm_encoder *sti_dvo_find_encoder(struct drm_device *dev)