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/lib/upgrade/platform.sh

@@ -0,0 +1,68 @@
+platform_do_upgrade() {
+	local board=$(board_name)
+
+	case "$board" in
+	unielec,u7623-02-emmc-512m)
+		#Keep the persisten random mac address (if it exists)
+		mkdir -p /tmp/recovery
+		mount -o rw,noatime /dev/mmcblk0p1 /tmp/recovery
+		[ -f "/tmp/recovery/mac_addr" ] && \
+			mv -f /tmp/recovery/mac_addr /tmp/
+		umount /tmp/recovery
+
+		#1310720 is the offset in bytes from the start of eMMC and to
+		#the location of the kernel (2560 512 byte sectors)
+		get_image "$1" | dd of=/dev/mmcblk0 bs=1310720 seek=1 conv=fsync
+
+		mount -o rw,noatime /dev/mmcblk0p1 /tmp/recovery
+		[ -f "/tmp/mac_addr" ] && mv -f /tmp/mac_addr /tmp/recovery
+		sync
+		umount /tmp/recovery
+		;;
+	*)
+		default_do_upgrade "$1"
+		;;
+	esac
+}
+
+PART_NAME=firmware
+
+platform_check_image() {
+	local board=$(board_name)
+	local magic="$(get_magic_long "$1")"
+
+	[ "$#" -gt 1 ] && return 1
+
+	case "$board" in
+	bananapi,bpi-r2|\
+	unielec,u7623-02-emmc-512m)
+		[ "$magic" != "27051956" ] && {
+			echo "Invalid image type."
+			return 1
+		}
+		return 0
+		;;
+	*)
+		echo "Sysupgrade is not supported on your board yet."
+		return 1
+		;;
+	esac
+
+	return 0
+}
+
+platform_copy_config_emmc() {
+	mkdir -p /recovery
+	mount -o rw,noatime /dev/mmcblk0p1 /recovery
+	cp -af "$UPGRADE_BACKUP" "/recovery/$BACKUP_FILE"
+	sync
+	umount /recovery
+}
+
+platform_copy_config() {
+	case "$(board_name)" in
+	unielec,u7623-02-emmc-512m)
+		platform_copy_config_emmc
+		;;
+	esac
+}