IB/mlx5: Use uid as part of PD commands

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

For example when a QP is created its uid must match the CQ uid which it
uses.

Next patches in this series will use the uid from the PD, then will come
a patch to set the uid on the PD so that all objects will be properly
work in one change.

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