IB/uverbs: Export uverbs idr and fd types

As provider drivers could use UVERBS_ATTR_FD and UVERBS_ATTR_IDR macros
need to export them.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>