IB: Replace ib_query_gid/ib_get_cached_gid with rdma_query_gid

If the gid_attr argument is NULL then the functions behave identically to
rdma_query_gid. ib_query_gid just calls ib_get_cached_gid, so everything
can be consolidated to one function.

Now that all callers either use rdma_query_gid() or ib_get_cached_gid(),
ib_query_gid() API is removed.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>