ltq-vdsl-app: add/enable missing G.993.2 XTSE bits

ltq-vdsl-app: add/enable missing G.993.2 XTSE bits

This patch adds the missing VDSL2 bits to the annex specific XTSE (like
it should be according to the comments above the XTSE bits).

Since r47933 it's mandatory to remove the annex option to switch to
VDSL2 (only) operation mode.

As shown by ticket #21436 and a few mails I received personally, even
experienced users are not aware that they have to remove the annex
option to get their VDSL2 line working and as shown by this patch it
doesn't need to be that "complicated".

Signed-off-by: Mathias Kresin <openwrt@kresin.me>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@48051 3c298f89-4303-0410-b956-a3cf2f4a3e73