sed: add '--read-only' to 'sed initialize'

sed: add '--read-only' to 'sed initialize'

By default 'sed initialize' will set the entire disk to read/write
locked, ie no access is possible. That is all fine if the BIOS supports
TCG Opal, as then the BIOS can unlock the drive before access.
But for BIOS _not_ supporting TCG Opal this results in an inaccessible
drive, and requires the user to use a different drive to boot and
unlock the SED device.
This patch adds a flag '--read-only' to 'nvme sed initlialize' such
that the 'read-lock enable' flag is not set for the locking range,
and the device continues to be readable by the BIOS for booting.

Signed-off-by: Hannes Reinecke <hare@suse.de>