tty: core: Add driver name to invalid device registration message

Include the driver name in the tty_register_device_attr() error
message for invalid index.

Note that tty_err() cannot be used here because there is no tty;
use pr_err().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/tty_io.c

@@ -3249,8 +3249,8 @@ struct device *tty_register_device_attr(struct tty_driver *driver,
 	bool cdev = false;
 
 	if (index >= driver->num) {
-		printk(KERN_ERR "Attempt to register invalid tty line number "
-		       " (%d).\n", index);
+		pr_err("%s: Attempt to register invalid tty line number (%d)\n",
+		       driver->name, index);
 		return ERR_PTR(-EINVAL);
 	}