RDMA/core: Fix empty gid table for non IB/RoCE devices

The query_gid_table ioctl skips non IB/RoCE ports, which as a result
returns an empty gid table for devices such as EFA which have a GID table,
but are not IB/RoCE.

Fixes: c4b4d548 ("RDMA/core: Introduce new GID table query API")
Link: https://lore.kernel.org/r/20201206153238.34878-1-galpress@amazon.com


Signed-off-by: Gal Pressman <galpress@amazon.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>