udf: implement mode and dmode mounting options

"dmode" allows overriding permissions of directories and
"mode" allows overriding permissions of files.

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/Documentation/filesystems/udf.txt b/Documentation/filesystems/udf.txt
index fde829a..902b95d 100644
--- a/Documentation/filesystems/udf.txt
+++ b/Documentation/filesystems/udf.txt
@@ -24,6 +24,8 @@
 
 	gid=		Set the default group.
 	umask=		Set the default umask.
+	mode=		Set the default file permissions.
+	dmode=		Set the default directory permissions.
 	uid=		Set the default user.
 	bs=		Set the block size.
 	unhide		Show otherwise hidden files.