sched: Fix accidental removal of errout goto

Bring back the goto that was removed by accident.

Reported-by: Colin Ian King <colin.king@canonical.com>
Fixes: 40c81b25

 ("sched: check negative err value to safe one level of indent")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>