1.Change query_gid hook to return value from IB/Core GID
  management APIs.
2.Get rid of all the netdev notifier chain subscription code as well
  as maintenance of SGID Table in memory.
3.Implement get_netdev hook in driver.
Signed-off-by: Somnath Kotur <somnath.kotur@avagotech.com>
Signed-off-by: Devesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>