When calculating the required size of an RC QP send queue, leave
enough space for masked atomic operations, which require more space than
"regular" atomic operation.

Fixes: 6fa8f719 ("IB/mlx4: Add support for masked atomic operations")
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Jack Morgenstein <jackm@mellanox.co.il>
Reviewed-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>