RDMA/rxe: Consider skb reserve space based on netdev of GID

RDMA/rxe: Consider skb reserve space based on netdev of GID

[ Upstream commit 3bf3e2b881c1412d0329ce9376dfe1518489b8fc ]

Always consider the skb reserve space based on netdevice of the GID
attribute, regardless of vlan or non vlan netdevice.

Fixes: 43c9fc509fa5 ("rdma_rxe: make rxe work over 802.1q VLAN devices")
Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>