Convert each element of the pages array to a folio before using it.  This
in no way renders the function large-folio safe, but it does remove a lot
of hidden calls to compound_head().

Link: https://lkml.kernel.org/r/20231016201114.1928083-20-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>