drm/sun4i: Fix error code in sun4i_tcon_bind()

We accidentally passed the wrong variable to PTR_ERR().

Fixes: a0c1214e ("drm/sun4i: Add LVDS support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180115081113.wlam5wkmdynisf4r@mwanda

drivers/gpu/drm/sun4i/sun4i_tcon.c

@@ -902,7 +902,7 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master,
 				has_lvds_alt = false;
 			} else {
 				dev_err(dev, "Couldn't get the LVDS PLL\n");
-				return PTR_ERR(tcon->lvds_rst);
+				return PTR_ERR(tcon->lvds_pll);
 			}
 		} else {
 			has_lvds_alt = true;