scsi: lpfc: ensure els_wq is being checked before destroying it

I believe there is a typo on the wq destroy of els_wq, currently the
driver is checking if els_cq is not null and I think this should be a
check on els_wq instead.

Detected by CoverityScan, CID#1411629 ("Copy-paste error")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>