Fix the "error: we previously assumed 'out_param' could be null" found
by smatch semantic checker on:
drivers/net/ethernet/mellanox/mlx4/cmd.c:506 mlx4_cmd_poll()
drivers/net/ethernet/mellanox/mlx4/cmd.c:578 mlx4_cmd_wait()
Signed-off-by: NEyal Perry <eyalpe@mellanox.com>
Signed-off-by: NAmir Vadai <amirv@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>