drm/xlnx/zynqmp_dp: Fix function name zynqmp_dp_link_train() -> zynqmp_dp_train()

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/xlnx/zynqmp_dp.c:793: warning: expecting prototype for zynqmp_dp_link_train(). Prototype was for zynqmp_dp_train() instead
Signed-off-by: Lee Jones <lee@kernel.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

drivers/gpu/drm/xlnx/zynqmp_dp.c

@@ -784,7 +784,7 @@ static int zynqmp_dp_link_train_ce(struct zynqmp_dp *dp)
 }
 
 /**
- * zynqmp_dp_link_train - Train the link
+ * zynqmp_dp_train - Train the link
  * @dp: DisplayPort IP core structure
  *
  * Return: 0 if all trains are done successfully, or corresponding error code.