md/raid5: don't set Faulty rdev for blocked_rdev

Faulty rdev should never be accessed anymore, hence there is no point to
wait for bad block to be acknowledged in this case while handling write
request.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Tested-by: Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>
Link: https://lore.kernel.org/r/20241031033114.3845582-8-yukuai1@huaweicloud.com


Signed-off-by: Song Liu <song@kernel.org>