[SCSI] qla2xxx: Remove a dead assignment in qla24xx_build_scsi_crc_2_iocbs().

Since the value of cur_seg is not used and since scsi_prot_sglist()
has no side effects it is safe to remove the statement
"cur_seg = scsi_port_sglist(cmd)". Detected by Coverity.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>