can: raw: raw_module_init(): use pr_err() instead of printk(KERN_ERR, ...)

This patch converts a printk(KERN_ERR, ...) to a pr_err().
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

net/can/raw.c

@@ -885,7 +885,7 @@ static __init int raw_module_init(void)
 
 	err = can_proto_register(&raw_can_proto);
 	if (err < 0)
-		printk(KERN_ERR "can: registration of raw protocol failed\n");
+		pr_err("can: registration of raw protocol failed\n");
 
 	return err;
 }