disp: msm: dp: fix potential NULL pointer dereference

Fix the potential NULL pointer dereference in the callback function
for HDCP status updates.

Change-Id: I57ffc480cc6a8f89db0d18151a07876aeeb8c236
Signed-off-by: Tatenda Chipeperekwa <[email protected]>

msm/dp/dp_display.c

@@ -581,14 +581,15 @@ static void dp_display_notify_hdcp_status_cb(void *ptr,
 		enum sde_hdcp_state state)
 {
 	struct dp_display_private *dp = ptr;
-	SDE_EVT32_EXTERNAL(SDE_EVTLOG_FUNC_ENTRY,
-					dp->link->hdcp_status.hdcp_state);
 
 	if (!dp) {
 		DP_ERR("invalid input\n");
 		return;
 	}
 
+	SDE_EVT32_EXTERNAL(SDE_EVTLOG_FUNC_ENTRY,
+					dp->link->hdcp_status.hdcp_state);
+
 	dp->link->hdcp_status.hdcp_state = state;
 
 	queue_delayed_work(dp->wq, &dp->hdcp_cb_work, HZ/4);