Input: cyttsp4 - silence NULL dereference warning

If "cd" were NULL then we would dereference it when we print the error
message.  Fortunately enough, it can't ever be NULL so we can remove
those lines.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/cyttsp4_core.c

@@ -1450,11 +1450,6 @@ static void cyttsp4_watchdog_work(struct work_struct *work)
 	u8 *mode;
 	int retval;
 
-	if (cd == NULL) {
-		dev_err(cd->dev, "%s: NULL context pointer\n", __func__);
-		return;
-	}
-
 	mutex_lock(&cd->system_lock);
 	retval = cyttsp4_load_status_regs(cd);
 	if (retval < 0) {