disp: msm: sde: fix vblank wait after cache read mode update

This change fixes the vblank wait after system cache read mode
update. Without this change the wait does not happen since there is
no pending kickoff. This change uses encoder api to flush the
configuration and explicitly waits for vblank.

Change-Id: I8942f9b638e784c8fd9b5df33a9ccc7087a5eaef
Signed-off-by: Abhijit Kulkarni <kabhijit@codeaurora.org>

msm/sde/sde_encoder.h

@@ -335,8 +335,10 @@ void sde_encoder_trigger_kickoff_pending(struct drm_encoder *encoder);
  * @encoder:	encoder pointer
  * @is_error:	whether the current commit needs to be aborted and replaced
  *		with a 'safe' commit
+ * @config_changed: if true new configuration is applied on the control path
  */
-void sde_encoder_kickoff(struct drm_encoder *encoder, bool is_error);
+void sde_encoder_kickoff(struct drm_encoder *encoder, bool is_error,
+		bool config_changed);
 
 /**
  * sde_encoder_wait_for_event - Waits for encoder events