losetup: fix outdated comment

From abb2a420924c792be33aa3ed825b1348ea7d51a9 Mon Sep 17 00:00:00 2001
From: "Yuriy M. Kaminskiy" <yumkam@gmail.com>
Date: Wed, 13 Apr 2016 17:30:10 +0300
Subject: [PATCH] losetup: fix outdated comment

--direct-io argument was made optional by
f98d9641a3, but this comment was not
updated accordingly

Signed-off-by: Yuriy M. Kaminskiy <yumkam@gmail.com>

sys-utils/losetup.c

@@ -626,7 +626,7 @@ int main(int argc, char **argv)
 		/*
 		 * losetup [--list] <device>
 		 * OR
-		 * losetup --direct-io DIO <device>
+		 * losetup --direct-io[=off] <device>
 		 */
 		if (!set_dio)
 			act = A_SHOW_ONE;