[SCSI] qla4xxx: Add support to get CHAP details for flash target session

Add support to get local CHAP - index, username and password,
sysfs params of iscsi session corresponding to flash target entry.

Signed-off-by: Adheer Chandravanshi <adheer.chandravanshi@qlogic.com>
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>