mm/swapfile.c: fix swap_count comment about nonexistent SWAP_HAS_CONT

Commit 570a335b ("swap_info: swap count continuations") introduces
COUNT_CONTINUED but refers to it incorrectly as SWAP_HAS_CONT in a
comment in swap_count.  Fix it.

Link: http://lkml.kernel.org/r/20180612175919.30413-1-daniel.m.jordan@oracle.com
Fixes: 570a335b ("swap_info: swap count continuations")
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/swapfile.c

@@ -100,7 +100,7 @@ atomic_t nr_rotate_swap = ATOMIC_INIT(0);
 
 static inline unsigned char swap_count(unsigned char ent)
 {
-	return ent & ~SWAP_HAS_CACHE;	/* may include SWAP_HAS_CONT flag */
+	return ent & ~SWAP_HAS_CACHE;	/* may include COUNT_CONTINUED flag */
 }
 
 /* returns 1 if swap entry is freed */