MFstable/10 r291185:

MFC r291047:

Don't leak work if __mlx4_register_vlan(..) fails in
mlx4_master_immediate_activate_vlan_qos(..)

Differential Revision: https://reviews.freebsd.org/D4203
Submitted by: Miles Olrich <miles.olrich@isilon.com>
Sponsored by: EMC / Isilon Storage Division