IB/mlx5: Set uid as part of RQ commands

Set uid as part of RQ commands so that the firmware can manage the
RQ object in a secured way.

The uid for the destroy command is set by mlx5_core.

This will enable using an RQ that was created by verbs application to
be used by the DEVX flow in case the uid is equal.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>