mm/vmscan: remove unused RECLAIM_OFF/RECLAIM_ZONE

Commit 1b2ffb78 ("[PATCH] Zone reclaim: Allow modification of zone
reclaim behavior")' defined RECLAIM_OFF/RECLAIM_ZONE, but never use
them, so better to remove them.

[dwagner@suse.de: fix sanity checks enabling]
  Link: http://lkml.kernel.org/r/20200116131642.642-1-dwagner@suse.de
[akpm@linux-foundation.org: renumber the bits for neatness]
Link: http://lkml.kernel.org/r/1579005573-58923-1-git-send-email-alex.shi@linux.alibaba.comSigned-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Tobin C. Harding" <tobin@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmscan.c

@@ -4110,10 +4110,8 @@ module_init(kswapd_init)
  */
 int node_reclaim_mode __read_mostly;
 
-#define RECLAIM_OFF 0
-#define RECLAIM_ZONE (1<<0)	/* Run shrink_inactive_list on the zone */
-#define RECLAIM_WRITE (1<<1)	/* Writeout pages during reclaim */
-#define RECLAIM_UNMAP (1<<2)	/* Unmap pages during reclaim */
+#define RECLAIM_WRITE (1<<0)	/* Writeout pages during reclaim */
+#define RECLAIM_UNMAP (1<<1)	/* Unmap pages during reclaim */
 
 /*
  * Priority for NODE_RECLAIM. This determines the fraction of pages