IB/mlx5: Allow transition of DCI QP to reset

The transition is allowed from any state and the atrribute mask must be
IB_QP_STATE.

Fixes: c32a4f29

 ("IB/mlx5: Add support for DC Initiator QP")
Signed-off-by: Moni Shoua <monis@mellanox.com>
Reviewed-by: Artemy Kovalyov <artemyko@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>