Introduce mlx5 data direct placement (DDP)

This feature allows WRs on the receiver side of the QP to be consumed
out of order, permitting the sender side to transmit messages without
guaranteeing arrival order on the receiver side.

When enabled, the completion ordering of WRs remains in-order,
regardless of the Receive WRs consumption order.

RDMA Read and RDMA Atomic operations on the responder side continue to
be executed in-order, while the ordering of data placement for RDMA
Write and Send operations is not guaranteed.

Signed-off-by: Leon Romanovsky <leon@kernel.org>

* mlx5-next:
  net/mlx5: Introduce data placement ordering bits