HID: roccat: silence an uninitialized variable warning

My static checker complains because we use "dev_id" before we check for
errors so it could be uninitialized.  Fix this by moving the error
handling forward a couple lines.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-roccat.c

@@ -421,14 +421,13 @@ static int __init roccat_init(void)
 
 	retval = alloc_chrdev_region(&dev_id, ROCCAT_FIRST_MINOR,
 			ROCCAT_MAX_DEVICES, "roccat");
-
-	roccat_major = MAJOR(dev_id);
-
 	if (retval < 0) {
 		pr_warn("can't get major number\n");
 		goto error;
 	}
 
+	roccat_major = MAJOR(dev_id);
+
 	cdev_init(&roccat_cdev, &roccat_ops);
 	retval = cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES);