IB/uverbs: Enable ioctl() uAPI by default for new verbs

Enable the ioctl() uAPI for IB by default if the standard write()
uAPI (INFINIBAND_USER_ACCESS) is enabled. Verbs that are
also available under the old write() uAPI are put inside a new
INFINIBAND_EXP_LEGACY_VERBS_NEW_UAPI Kconfig.

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