drm: rcar-du: Fix compilation warning

Commit d63c25e424 ("drm: rcar-du: Use generic
drm_connector_register_all() helper") left an unused local variable
behind. Remove it.

Fixes: d63c25e424 ("drm: rcar-du: Use generic drm_connector_register_all() helper")
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

drivers/gpu/drm/rcar-du/rcar_du_drv.c

@@ -297,7 +297,6 @@ static int rcar_du_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
 	struct rcar_du_device *rcdu;
-	struct drm_connector *connector;
 	struct drm_device *ddev;
 	struct resource *mem;
 	int ret;