scsi: ufs: core: Cancel rpm_dev_flush_recheck_work during system suspend

During ufs system suspend, leaving rpm_dev_flush_recheck_work running or
pending is risky because concurrency may happen between system
suspend/resume and runtime resume routine. Fix this by cancelling
rpm_dev_flush_recheck_work synchronously during system suspend.

Link: https://lore.kernel.org/r/1619408921-30426-3-git-send-email-cang@codeaurora.org


Fixes: 51dd905b ("scsi: ufs: Fix WriteBooster flush during runtime suspend")
Reviewed-by: Daejun Park <daejun7.park@samsung.com>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>