md/raid5: implement pers->bitmap_sector()

commit 9c89f604 upstream.

Bitmap is used for the whole array for raid1/raid10, hence IO for the
array can be used directly for bitmap. However, bitmap is used for
underlying disks for raid5, hence IO for the array can't be used
directly for bitmap.

Implement pers->bitmap_sector() for raid5 to convert IO ranges from the
array to the underlying disks.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20250109015145.158868-5-yukuai1@huaweicloud.com


Signed-off-by: Song Liu <song@kernel.org>
[ Resolve minor conflicts ]
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>