sed-opal: refactor (split) IOC_OPAL_LR_SETUP internals.

sed-opal: refactor (split) IOC_OPAL_LR_SETUP internals.

IOC_OPAL_LR_SETUP is used to set up a locking range entirely under a
single authority (usually Admin1), but for Single User Mode (SUM),
the permissions for attributes (RangeStart, RangeLength)
and (ReadLockEnable, WriteLockEnable, ReadLocked, WriteLocked)
may be split between two different authorities. Typically, it is Admin1
for the former and the User associated with the LockingRange in SUM
for the latter.

This commit only splits the internals in preparation for the introduction
of separate ioctls for setting RangeStart, RangeLength and the rest
using new ioctl calls.

Signed-off-by: Ondrej Kozina <okozina@redhat.com>
Reviewed-and-tested-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>