IB/mlx4: Fix create CQ error flow

Currently, if ib_copy_to_udata fails, the CQ
won't be deleted from the radix tree and the HW (HW2SW).

Fixes: 225c7b1f

 ('IB/mlx4: Add a driver Mellanox ConnectX InfiniBand adapters')
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>