md/raid10: fix improper BUG_ON() in raise_barrier()

mainline inclusion
from mainline-v6.1-rc1
commit 4f350284
category: bugfix
bugzilla: 188015, https://gitee.com/openeuler/kernel/issues/I63WZE

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/commit/?id=4f350284a7306b3dff676caeafd3faf1b5c068d5



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'conf->barrier' is protected by 'conf->resync_lock', reading
'conf->barrier' without holding the lock is wrong.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Guoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Li Nan <linan122@huawei.com>