LU-19045 build: memfs_write_end can be passed a folio

LU-19045 build: memfs_write_end can be passed a folio

Linux v6.11-rc1-51-ga225800f322a
 fs: Convert aops->write_end to take a folio
Linux v6.11-rc1-52-g1da86618bdce
 fs: Convert aops->write_begin to take a folio
Add 'struct folio' for page vs folio signature change.

Fixes: 25813cf8ba ("LU-18813 osd-wbcfs: MemFS-based OSD with writeback support")
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Change-Id: I1cf87ac70c52652530e4fbc853c5160dc5822ec9
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/59393
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Timothy Day <timday@amazon.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>