vfat: Note the NLS requirement

Close bug #4754. Stop people getting into a situation where they can't
get their FAT filesystems to mount as they expect.
Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/fat/Kconfig

@@ -95,3 +95,6 @@ config FAT_DEFAULT_IOCHARSET
 	  Note that "utf8" is not recommended for FAT filesystems.
 	  If unsure, you shouldn't set "utf8" here.
 	  See <file:Documentation/filesystems/vfat.txt> for more information.
+
+	  Enable any character sets you need in File Systems/Native Language
+	  Support.