scsi: qedi: Remove set but not used variable 'cls_sess'

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

drivers/scsi/qedi/qedi_fw.c: In function 'qedi_tmf_resp_work':
drivers/scsi/qedi/qedi_fw.c:158:28: warning:
 variable 'cls_sess' set but not used [-Wunused-but-set-variable]

drivers/scsi/qedi/qedi_fw.c: In function 'qedi_tmf_work':
drivers/scsi/qedi/qedi_fw.c:1370:28: warning:
 variable 'cls_sess' set but not used [-Wunused-but-set-variable]

It's never used since introduction.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>