nilfs2: convert nilfs_recovery_copy_block() to take a folio

Use memcpy_to_folio() instead of open-coding it, and use offset_in_folio()
in case anybody wants to use nilfs2 on a device with large blocks.

[konishi.ryusuke@gmail.com: added label name change]
Link: https://lkml.kernel.org/r/20241002150036.1339475-4-willy@infradead.org
Link: https://lkml.kernel.org/r/20241024092602.13395-12-konishi.ryusuke@gmail.com


Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>