Now that the IB core GID cache ensures that a zero GID doesn't exist in
the GID table remove zero GID checks from the provider drivers for
clarity.
Reviewed-by: NMark Bloch <markb@mellanox.com>
Signed-off-by: NParav Pandit <parav@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>