mediatek: mt7629: fix ethernet default config

1. fix typo: ucidef_set_interfaces_wan -> ucidef_set_interface_wan
2. change board name to mt7629-rfb to match upstream dts

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>

target/linux/mediatek/mt7629/base-files/etc/board.d/02_network

@@ -9,8 +9,8 @@ mediatek_setup_interfaces()
 	local board="$1"
 
 	case $board in
-	mediatek,mt7629-lynx-rfb)
-		ucidef_set_interfaces_wan "eth1"
+	mediatek,mt7629-rfb)
+		ucidef_set_interface_wan "eth1"
 		ucidef_add_switch "switch0" \
 			"0:lan" "1:lan" "2:lan" "3:lan" "6@eth0"
 		;;