[VLAN]: MAINTAINERS update

Ben stepped down from VLAN maintainership due to a lack of time, add
myself as new maintainer.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>