mediatek: split base-files into subtargets

This splits some base-files across subtargets, as done previously
on ath79 and ramips and also introduced for mt7629 subtarget here
already. Most of the existing base-files content is specific to
mt7623.

While at it, apply the following fixes:
- Remove lots of trailing whitespaces
- Remove wildcard on unielec,u7623-02-emmc-512m
- Remove inconsistent quotation marks in cases

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Acked-by: John Crispin <john@phrozen.org>

target/linux/mediatek/mt7623/base-files/etc/board.d/02_network

@@ -0,0 +1,40 @@
+#!/bin/sh
+
+. /lib/functions.sh
+. /lib/functions/uci-defaults.sh
+. /lib/functions/system.sh
+
+mediatek_setup_interfaces()
+{
+	local board="$1"
+
+	case $board in
+	mediatek,mt7623a-rfb-emmc)
+		ucidef_set_interface_lan "lan0 lan1 lan2 lan3"
+		ucidef_set_interface_wan eth1
+		;;
+	bananapi,bpi-r2|\
+	unielec,u7623-02-emmc-512m)
+		ucidef_set_interfaces_lan_wan "lan0 lan1 lan2 lan3" "wan"
+		;;
+	esac
+}
+
+mediatek_setup_macs()
+{
+	local board="$1"
+
+	case $board in
+	unielec,u7623-02-emmc-512m)
+		ucidef_set_interface_macaddr "wan" "$(cat /sys/class/net/wan/address)"
+		;;
+	esac
+}
+
+board_config_update
+board=$(board_name)
+mediatek_setup_interfaces $board
+mediatek_setup_macs $board
+board_config_flush
+
+exit 0