vlan: Export symbols as non GPL symbols.

In previous kernels, any kernel module could get access to the
'real-device' and the VLAN-ID for a particular VLAN.  In more recent
kernels, the code was restructured such that this is hard to do
without accessing private .h files for any module that cannot use
GPL-only symbols.

Attached is a patch to once again allow non-GPL modules the ability to
access the real-device and VLAN id for VLANs.

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