lantiq-xrx200: remove obsolete dsl-app again

ltq-vdsl-app was renamed to ltq-vdsl-vr9-app
https://github.com/openwrt/openwrt/commit/33e2115fe449d1b9e97ce8c5be96f580442fd3d9
ltq-dsl-base is a new package that was added with 23.05

targets/lantiq-xrx200

@@ -5,10 +5,11 @@ packages {
 	'-kmod-ltq-atm-vr9',
 	'-kmod-ltq-ptm-vr9',
 	'-kmod-ltq-deu-vr9',
-	'-ltq-vdsl-app',
+	'-ltq-vdsl-vr9-app',
 	'-dsl-vrx200-firmware-xdsl-a',
 	'-dsl-vrx200-firmware-xdsl-b-patch',
 	'-ppp-mod-pppoa',
+	'-ltq-dsl-base',
 }