scsi: qla2xxx: fix NPIV tear down process

Fix two issues with commit f5187b7d ("scsi: qla2xxx: Optimize NPIV
tear down process"): a missing negation in a wait_event_timeout()
condition, and a missing loop end condition.

Fixes: f5187b7d

 ("scsi: qla2xxx: Optimize NPIV tear down process")
Link: https://lore.kernel.org/r/20191105145550.10268-1-martin.wilck@suse.com
Signed-off-by: Martin Wilck <mwilck@suse.com>
Acked-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>