[SCSI] iscsi class: Replace iscsi_get_next_target_id with IDA
Replaced the iscsi_get_next_target_id with IDA to make
target-id allocation efficient for iscsi offload drivers
This patch should be applied after Jonathen Cameron Patch
"ida : simplified functions for id allocation"
Signed-off-by: John Soni Jose <jose0here@gmail.com> Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: James Bottomley <JBottomley@Parallels.com>