mtd: plat-ram: remove redundant dev_err call in platram_probe()

There is a error message within devm_ioremap_resource
already, so remove the dev_err call to avoid redundant
error message.

Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: Yu Kuai <[e-mail]>
Signed-off-by: Miquel Raynal <[e-mail]>
Link: https://lore.kernel.org/linux-mtd/[e-mail]

drivers/mtd/maps/plat-ram.c

···
 	info->map.virt = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(info->map.virt)) {
 		err = PTR_ERR(info->map.virt);
-		dev_err(&pdev->dev, "failed to ioremap() region\n");
 		goto exit_free;
 	}