net/mlx5: Set uid as part of DCT commands

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

That will enable using a DCT 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>