sed-opal: add IOC_OPAL_ENABLE_DISABLE_LR.

sed-opal: add IOC_OPAL_ENABLE_DISABLE_LR.

This ioctl is used to set up RLE (read lock enabled) and WLE (write
lock enabled) parameters of the Locking object.

In Single User Mode (SUM), if the RangeStartRangeLengthPolicy parameter
is set in the 'Reactivate' method, only Admin authority maintains the
locking range length and start (offset) attributes of Locking objects
set up for SUM. All other attributes from struct opal_user_lr_setup
(RLE - read locking enabled, WLE - write locking enabled) shall
remain in possession of the User authority associated with the Locking
object set for SUM.

With the IOC_OPAL_ENABLE_DISABLE_LR ioctl, the opal_user_lr_setup
members 'range_start' and 'range_length' of the ioctl argument are
ignored.

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>