drm/sun4i: Remove redundant dev_err call in sun4i_tcon_init_regmap()

There is a error message within devm_ioremap_resource
already, so remove the dev_err call to avoid redundant
error message.
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

drivers/gpu/drm/sun4i/sun4i_tcon.c

@@ -374,10 +374,8 @@ static int sun4i_tcon_init_regmap(struct device *dev,
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	regs = devm_ioremap_resource(dev, res);
-	if (IS_ERR(regs)) {
-		dev_err(dev, "Couldn't map the TCON registers\n");
+	if (IS_ERR(regs))
 		return PTR_ERR(regs);
-	}
 
 	tcon->regs = devm_regmap_init_mmio(dev, regs,
 					   &sun4i_tcon_regmap_config);