scsi: bnx2i: remove set but not used variable 'cid_num'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/scsi/bnx2i/bnx2i_hwi.c: In function 'bnx2i_process_ofld_cmpl':
drivers/scsi/bnx2i/bnx2i_hwi.c:2430:6: warning:
 variable 'cid_num' set but not used [-Wunused-but-set-variable]

It never used since commit
  cf4e6363 ("[SCSI] bnx2i: Add bnx2i iSCSI driver.")

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Nilesh Javali <nilesh.javali@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>