RDMA/rxe: Remove VLAN code leftovers from RXE

RDMA/rxe: Remove VLAN code leftovers from RXE

Since the commit fd49ddaf7e26 ("RDMA/rxe: prevent rxe creation on top of
vlan interface") does not permit rxe on top of vlan device, all the stuff
related with vlan should be removed.

Fixes: fd49ddaf7e26 ("RDMA/rxe: prevent rxe creation on top of vlan interface")
Link: https://lore.kernel.org/r/1604326422-18625-1-git-send-email-yanjunz@nvidia.com
Signed-off-by: Zhu Yanjun <yanjunz@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>