[SCSI] remove flush_scheduled_work() usages

Simple conversions to drop flush_scheduled_work() usages in
drivers/scsi.  More involved ones will be done in separate patches.

* NCR5380, megaraid_sas: cancel_delayed_work() +
  flush_scheduled_work() -> cancel_delayed_work_sync().

* mpt2sas_scsih: drop unnecessary flush_scheduled_work().

* arcmsr_hba, ipr, pmcraid: flush the used work explicitly instead of
  using flush_scheduled_work().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 9c5c8be..a8e24f0 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -8865,7 +8865,7 @@
 
 	spin_unlock_irqrestore(ioa_cfg->host->host_lock, host_lock_flags);
 	wait_event(ioa_cfg->reset_wait_q, !ioa_cfg->in_reset_reload);
-	flush_scheduled_work();
+	flush_work_sync(&ioa_cfg->work_q);
 	spin_lock_irqsave(ioa_cfg->host->host_lock, host_lock_flags);
 
 	spin_lock(&ipr_driver_lock);