mount options: fix fat

Add flush option to /proc/mounts for msdos and vfat filesystems.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/fat/inode.c

@@ -837,6 +837,8 @@ static int fat_show_options(struct seq_file *m, struct vfsmount *mnt)
 		if (!opts->numtail)
 			seq_puts(m, ",nonumtail");
 	}
+	if (sbi->options.flush)
+		seq_puts(m, ",flush");
 
 	return 0;
 }