net/mlx5: Set uid as part of CQ commands

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

The firmware should mark this CQ with the given uid so that it can
be used later on only by objects with the same uid.

Upon DEVX flows that use this CQ (e.g. create QP command), the
pointed CQ must have the same uid as of the issuer uid command.

When a command is issued with uid=0 it means that the issuer of the
command is trusted (i.e. kernel), in that case any pointed object
can be used regardless of its uid.

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