BACKPORT: mm: convert unuse_pte() to use a folio throughout

Saves about eight calls to compound_head().

Link: https://lkml.kernel.org/r/20231211162214.2146080-4-willy@infradead.org


Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit f00f4843)
[ Fix some trivial conflicts in mm/swapfile.c due to
  commit f238b8c3
  already backported to ACK15.6.6 - Kalesh Singh ]
Bug: 313807618
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Change-Id: I7400455786d0b5774cadc2a223f524325826faf7