Revert "mm: add private field of first tail to struct page and struct folio"

This reverts commit 271227f1 which is
commit d340625f upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: Idb42cdd16d37a180911fe1a335744c02aaf683dc
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>