query_gid() should return right GID value for iWarp and IB link layers.
It is a no-op for RoCE link layer.  Update the documentation to reflect
this.
Signed-off-by: NParav Pandit <parav@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>