IB/cache: Restore compatibility for ib_query_gid

Code changes in smc have become so complicated this cycle that the RDMA
patches to remove ib_query_gid in smc create too complex merge conflicts.
Allow those conflicts to be resolved by using the net/smc hunks by
providing a compatibility wrapper. During the second phase of the merge
window this wrapper will be deleted and smc updated to use the new API.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>