IB/ipoib: Add ndo operations for configuring VFs

Add ndo operations to the network driver that enables configuring the
following operations:

ipoib_set_vf_link_state - configure the VF link policy
ipoib_get_vf_config - get link state configuration
ipoib_set_vf_guid - set a VF port or node GUID
ipoib_get_vf_stats - get statistics of a VF

Signed-off-by: Eli Cohen <eli@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>