The DSA switch VLAN ops pass the switchdev_trans structure down to the
drivers, but no one is using them and they aren't supposed to anyway.

Remove the trans argument from VLAN prepare and add operations.

At the same time, fix the following checkpatch warning:

    WARNING: line over 80 characters
    #74: FILE: drivers/net/dsa/dsa_loop.c:177:
    +				      const struct switchdev_obj_port_vlan *vlan)
Signed-off-by: NVivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>