mm/vmscan: cleanup comment error in balance_pgdat

Signed-off-by: Wanpeng Li <liwp.linux@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 091ab8f..3d1365c 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2864,7 +2864,7 @@
 				 * consider it to be no longer congested. It's
 				 * possible there are dirty pages backed by
 				 * congested BDIs but as pressure is relieved,
-				 * spectulatively avoid congestion waits
+				 * speculatively avoid congestion waits
 				 */
 				zone_clear_flag(zone, ZONE_CONGESTED);
 				if (i <= *classzone_idx)