Add SCSI passthrough to CTL

[Bhimanshu Kumar]

*Introduction : *CTL is the FreeBSD SCSI target layer. There are various
SCSI commands, but it's usually used for block-level access. This projects
focuses on making CTL capable of providing physical optical drive as a
whole to the initiator machine
Link : https://github.com/bhimanshu1997/freebsd

Report for last week (17th July)
1. ctld(8) kernel.c code updated for passthrough-device and address luns.
2. code added to distinguish device or address type of passthrough , to
create appropriate request to create lun
3. checks added for size and path with passthrough. No size and path should
be set if it is passthrough.
4. conf_apply of ctld.c updated to check new and old lun on the basis of
passthrough and passthrough, lun and passthrough , passthrough and lun.
keeping the older functionality (lun and lun) intact.



Report for this week(24th july):
1. XML parse coded added in CTL (ctl.c) and at ctladm side also. now ctladm
devlist -vx will give passthrough details also in XML format.