md/raid1,raid10: support narrow_write_error when badblocks is disabled

md/raid1,raid10: support narrow_write_error when badblocks is disabled

When badblocks.shift < 0 (badblocks disabled), narrow_write_error()
return false, preventing write error handling. Since narrow_write_error()
only splits IO into smaller sizes and re-submits, it can work with
badblocks disabled.

Adjust to use the logical block size for block_sectors when badblocks is
disabled, allowing narrow_write_error() to function in this case.

Link: https://lore.kernel.org/linux-raid/20260105110300.1442509-4-linan666@huaweicloud.com
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai@fnnas.com>
Signed-off-by: Yu Kuai <yukuai@fnnas.com>