UPSTREAM: include/linux/page-flags-layout.h: cleanups

Tidy things up and delete comments stating the obvious with typos or
making no sense.

Link: https://lkml.kernel.org/r/20210303071609.797782-2-yuzhao@google.com


Signed-off-by: Yu Zhao <yuzhao@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 1587db62)
Bug: 227651406
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Change-Id: I1d57992dd4c68d89c1b9180f280e09d5d08482b6