md: fix data corruption for raid456 when reshape restart while grow up

stable inclusion
from stable-v5.10.188
commit b02939413e5c9bbea58e220c1e9733930edb6d1a
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8KYFP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b02939413e5c9bbea58e220c1e9733930edb6d1a



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[ Upstream commit 873f50ec ]

Currently, if reshape is interrupted, echo "reshape" to sync_action will
restart reshape from scratch, for example:

echo frozen > sync_action
echo reshape > sync_action

This will corrupt data before reshape_position if the array is growing,
fix the problem by continue reshape from reshape_position.

Reported-by: Peter Neuwirth <reddunur@online.de>
Link: https://lore.kernel.org/linux-raid/e2f96772-bfbc-f43b-6da1-f520e5164536@online.de/


Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230512015610.821290-3-yukuai1@huaweicloud.com


Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>