Adding SCSI Passthrough to CTL

[suraj ponugoti]

 Hi,

This project is about exporting physical SCSI devices over iSCSI through CTL as an actual SCSI target.

Wiki Page: https://wiki.freebsd.org/SurajPonugoti
Git Repo: https://github.com/suraj5/freebsd

Weekly updates: I was able to create new peripheral device(passthrough) for all the scsi devices. I made few changes to ctl code, so all the ccb  of luntypes passthrough are send to passthrough driver.

In passthrough driver all the ccb of ctl are converted to cam ccb and then they are passed to incoming queue. Once they are processed they are passed to done_queue. From done_queue I will be passing those back to ctl done_queue.

Thanks
Suraj