scsi: message: fusion: Avoid flush_scheduled_work() usage

Like commit c4f135d6 ("workqueue: Wrap flush_workqueue() using a
macro") says, flush_scheduled_work() is dangerous and will be forbidden.

Commit 4d4109d0 ("[SCSI] mpt fusion: Power Management fixes for MPT SAS
PCI-E controllers") added flush_scheduled_work() call into
mptscsih_suspend().  As of commit 4d4109d0, there were several
schedule{,_delayed}_work() calls where flush_scheduled_work() from
mptscsih_suspend() meant to wait for completion. However, which work items
this flush_scheduled_work() call was for was not explained.

Then, schedule_work("struct mptsas_hotplug_event"->work) and
schedule_work(MPT_ADAPTER->sas_persist_task) have been removed by commit
3eb0822c ("[SCSI] mpt fusion: Firmware event implementation using
seperate WorkQueue"), and schedule_work("struct
mptsas_send_discovery_event"->work) has been removed by commit f9c34022
("[SCSI] mpt fusion: SAS topology scan changes, expander events").

There still remains schedule_work("struct work_queue_wrapper"->work) call
in mptspi.c and schedule_delayed_work("struct mpt_lan_priv"->work) call in
mptlan.c , but I guess that these are not work items which commit
4d4109d0 meant to wait for completion because these are not per
MPT_ADAPTER work items. If my guess is correct, we no longer need to call
flush_scheduled_work() from mptscsih_suspend().

Link: https://lore.kernel.org/r/0b9ebcfb-b647-1381-0653-b54528a64a86@I-love.SAKURA.ne.jpSigned-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/message/fusion/mptscsih.c

@@ -1231,7 +1231,6 @@ mptscsih_suspend(struct pci_dev *pdev, pm_message_t state)
 	MPT_ADAPTER 		*ioc = pci_get_drvdata(pdev);
 
 	scsi_block_requests(ioc->sh);
-	flush_scheduled_work();
 	mptscsih_shutdown(pdev);
 	return mpt_suspend(pdev,state);
 }