drm: omapdrm: Simplify DSS power management

Instead of sprinkling dispc_runtime_get() and dispc_runtime_put() calls
in various CRTC operations, move all power management code to the atomic
commit function.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c
index 2e77063..50f5555 100644
--- a/drivers/gpu/drm/omapdrm/omap_drv.c
+++ b/drivers/gpu/drm/omapdrm/omap_drv.c
@@ -73,6 +73,8 @@
 	struct drm_atomic_state *old_state = commit->state;
 
 	/* Apply the atomic update. */
+	dispc_runtime_get();
+
 	drm_atomic_helper_commit_modeset_disables(dev, old_state);
 	drm_atomic_helper_commit_planes(dev, old_state);
 	drm_atomic_helper_commit_modeset_enables(dev, old_state);
@@ -81,6 +83,8 @@
 
 	drm_atomic_helper_cleanup_planes(dev, old_state);
 
+	dispc_runtime_put();
+
 	drm_atomic_state_free(old_state);
 
 	/* Complete the commit, wake up any waiter. */