tools/memory-model: Fix typo in klitmus7 compatibility table

klitmus7 of herdtools7 7.48 or earlier depends on ACCESS_ONCE(),
which was removed in Linux v4.15.
Fix the obvious typo in the table.

Fixes: d075a78a5ab1 ("tools/memory-model/README: Expand dependency of klitmus7")
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
diff --git a/tools/memory-model/README b/tools/memory-model/README
index 39d08d1..9a84c45 100644
--- a/tools/memory-model/README
+++ b/tools/memory-model/README
@@ -51,7 +51,7 @@
 	============  ==========
 	target Linux  herdtools7
 	------------  ----------
-	     -- 4.18  7.48 --
+	     -- 4.14  7.48 --
 	4.15 -- 4.19  7.49 --
 	4.20 -- 5.5   7.54 --
 	5.6  --       7.56 --