RDMA/mlx5: Change the key being sent for MPV device affiliation

RDMA/mlx5: Change the key being sent for MPV device affiliation

Change the key that we send from IB driver to EN driver regarding the
MPV device affiliation, since at that stage the IB device is not yet
initialized, so its index would be zero for different IB devices and
cause wrong associations between unrelated master and slave devices.

Instead use a unique value from inside the core device which is already
initialized at this stage.

Fixes: 0d293714ac32 ("RDMA/mlx5: Send events from IB driver about device affiliation state")
Signed-off-by: Patrisious Haddad <phaddad@nvidia.com>
Link: https://lore.kernel.org/r/ac7e66357d963fc68d7a419515180212c96d137d.1697705185.git.leon@kernel.org
Signed-off-by: Leon Romanovsky <leon@kernel.org>