md: use msleep() in md_notify_reboot()

mainline inclusion
from mainline-v5.18-rc1
commit 7d959f6e
category: bugfix
bugzilla: 188015, https://gitee.com/openeuler/kernel/issues/I6OERX
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/commit/?id=7d959f6e978cbbca90e26a192cc39480e977182f



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

Calling mdelay(1000) from process context, even while a reboot
is in progress, does not make sense.

Using msleep() allows other threads to make progress.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: linux-raid@vger.kernel.org
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>