mm,hugetlb: rename anon_rmap to new_anon_folio and make it boolean

mm,hugetlb: rename anon_rmap to new_anon_folio and make it boolean

anon_rmap is used to determine whether the new allocated folio is
anonymous.  Rename it to something more meaningul like new_anon_folio and
make it boolean, as we use it like that.

While we are at it, drop 'new_pagecache_folio' as 'new_anon_folio' is
enough to check whether we need to restore the consumed reservation.

Link: https://lkml.kernel.org/r/20250627102904.107202-4-osalvador@suse.de
Link: https://lkml.kernel.org/r/20250630144212.156938-4-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Gavin Guo <gavinguo@igalia.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>