mtd: rawnand: Fix return value check of wait_for_completion_timeout

stable inclusion
from stable-4.19.242
commit abe55c894249e5fca4a0356dd519ea38de6586a7
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5A6BA


CVE: NA

--------------------------------

[ Upstream commit 084c16ab ]

wait_for_completion_timeout() returns unsigned long not int.
It returns 0 if timed out, and positive if completed.
The check for <= 0 is ambiguous and should be == 0 here
indicating timeout which is the only error case.

Fixes: 83738d87 ("mtd: sh_flctl: Add DMA capabilty")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220412083435.29254-1-linmq006@gmail.com


Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>