BACKPORT: mm: remove PageAnonExclusive assertions in unuse_pte()

The page in question is either freshly allocated or known to be in
the swap cache; these assertions are not particularly useful.

Link: https://lkml.kernel.org/r/20231212164813.2540119-1-willy@infradead.org


Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit 8d294a8c)
[ Fix trivial conflict in mm/swapfile.c - Kalesh Singh ]
Bug: 313807618
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Change-Id: I932718a3dbe7216c6119ff666406ff0661a97298