IB/cm: Remove dgid from the cm_id_priv av

It turns out this is only being used to store the LID for SIDR mode to
search the RB tree for request de-duplication. Store the LID value
directly and don't pretend it is a GID.

Link: https://lore.kernel.org/r/2e7c87b6f662c90c642fc1838e363ad3e6ef14a4.1623236345.git.leonro@nvidia.com


Reviewed-by: Mark Zhang <markzhang@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>