[SCSI] qla4xxx: Boot from SAN support for open-iscsi

Hook qla4xxx in fw boot sysfs interface so iscsi tools
can use the info to create boot sessions.

Signed-off-by: Manish Rangankar <manish.rangankar@qlogic.com>
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>