platform: msm_shared: add MDP support for HDMI

Setup pipe, mixer, DSPP and TG for HDMI interface. Currently
only one interface can be active in LK. If HDMI is selected as
primary, LK will boot with HDMI as only interface.

Change-Id: I37c08ccf911d7a1daa065436c617c2c6c7101a4d
diff --git a/platform/msm_shared/mdp4.c b/platform/msm_shared/mdp4.c
index 7b7c0cf..5bc4a84 100644
--- a/platform/msm_shared/mdp4.c
+++ b/platform/msm_shared/mdp4.c
@@ -423,3 +423,18 @@
 {
 	return NO_ERROR;
 }
+
+int mdp_hdmi_config(struct msm_panel_info *pinfo, struct fbcon_config *fb)
+{
+	return NO_ERROR;
+}
+
+int mdp_hdmi_on(void)
+{
+	return NO_ERROR;
+}
+
+int mdp_hdmi_off(void)
+{
+	return NO_ERROR;
+}