ramips: add support for Zyxel NBG-419N2 (WAP3205v2)

applied bb-final-ramips-add-zyxel-nbg-419n2.patch from
123serge123, found at https://yadi.sk/d/1ZV0lKJwbTE65;
see https://forum.openwrt.org/viewtopic.php?pid=246905#p246905,
modified slightly to fit to CC release and to new lede build
system: image/rt305x.mk include file is used now
changed NBG-419N2.dts format to fit style of other dts files

Signed-off-by: Klaus <k-laus@quantentunnel.de>

target/linux/ramips/base-files/lib/ramips.sh

@@ -325,6 +325,9 @@ ramips_board_detect() {
 	*"NBG-419N")
 		name="nbg-419n"
 		;;
+	*"NBG-419N v2")
+		name="nbg-419n2"
+		;;
 	*"Newifi-D1")
 		name="newifi-d1"
 		;;

target/linux/ramips/base-files/lib/upgrade/platform.sh

@@ -96,6 +96,7 @@ platform_check_image() {
 	mzk-w300nh2|\
 	mzk-wdpr|\
 	nbg-419n|\
+	nbg-419n2|\
 	newifi-d1|\
 	nixcore|\
 	nw718|\