ocfs2: convert ocfs2_duplicate_clusters_by_page() to use a folio

Retrieve folios from the page cache, not pages, and use a folio throughout
this function.  Removes seven calls to compound_head().

Link: https://lkml.kernel.org/r/20241205171653.3179945-18-willy@infradead.org


Signed-off-by: Mark Tinguely <mark.tinguely@oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Mark Fasheh <mark@fasheh.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>