All callers have a folio so we can remove this use of
page_ref_sub_return().

Link: https://lkml.kernel.org/r/20240424191914.361554-4-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>