mm: remove PageOwnerPriv1

While there are many aliases for this flag, nobody actually uses the
*PageOwnerPriv1() nor folio_*_owner_priv_1() accessors.  Remove them.

Link: https://lkml.kernel.org/r/20240821193445.2294269-8-willy@infradead.org


Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>