ramips: add support for ELECOM WRC-1167FS

ELECOM WRC-1167FS is a 2.4/5 GHz band 11ac (WiFi-5) router, based on
MT7628AN.

Specification:

- SoC		: MediaTek MT7628AN
- RAM		: DDR2 64 MiB (NT5TU32M16FG-AC)
- Flash		: SPI-NOR 16 MiB (W25Q128JVSIQ)
- WLAN		: 2.4/5 GHz 2T2R
  - 2.4 GHz	: MediaTek MT7628AN (SoC)
  - 5 GHz	: MediaTek MT7612E
- Ethernet	: 10/100 Mbps x2
  - Switch	: MT7628AN (SoC)
- LEDs/Keys	: 6x, 3x (2x buttons, 1x slide-switch)
- UART		: through-hole on PCB
  - J1: 3.3V, GND, TX, RX from "J1" marking
  - 57600n8
- Power		: 12 VDC, 1 A

Flash instruction using factory image:

1. Boot WRC-1167FS normally
2. Access to "http://192.168.2.1/" and open firmware update page
   ("ファームウェア更新")
3. Select the OpenWrt factory image and click apply ("適用") button to
   perform firmware update
4. Wait ~120 seconds to complete flashing

Notes:

- Last 0x800000 (8 MiB) in SPI-NOR flash is not used on stock firmware

- Additional padding in factory image is required to avoid incomplete
  flashing on stock firmware

MAC addresses:

- LAN	: BC:5C:4C:xx:xx:68 (Config, ethaddr (text) / Factory, 0x28   (hex))
- WAN	: BC:5C:4C:xx:xx:69 (Config, wanaddr (text) / Factory, 0x22   (hex))
- 2.4GHz: BC:5C:4C:xx:xx:6A (Config, rmac    (text) / Factory, 0x4    (hex))
- 5GHz	: BC:5C:4C:xx:xx:6B (Config, rmac2   (text) / Factory, 0x8004 (hex))

Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>

target/linux/ramips/image/mt76x8.mk

@@ -6,6 +6,21 @@ include ./common-tp-link.mk
 
 DEFAULT_SOC := mt7628an
 
+define Build/elecom-header
+	$(eval model_id=$(1))
+	( \
+		fw_size="$$(printf '%08x' $$(stat -c%s $@))"; \
+		echo -ne "$$(echo "031d6129$${fw_size}06000000$(model_id)" | \
+			sed 's/../\\x&/g')"; \
+		dd if=/dev/zero bs=92 count=1; \
+		data_crc="$$(dd if=$@ | gzip -c | tail -c 8 | \
+			od -An -N4 -tx4 --endian little | tr -d ' \n')"; \
+		echo -ne "$$(echo "$${data_crc}00000000" | sed 's/../\\x&/g')"; \
+		dd if=$@; \
+	) > $@.new
+	mv $@.new $@
+endef
+
 define Build/ravpower-wd009-factory
 	mkimage -A mips -T standalone -C none -a 0x80010000 -e 0x80010000 \
 		-n "OpenWrt Bootloader" -d $(UBOOT_PATH) $@.new
@@ -93,6 +108,18 @@ define Device/duzun_dm06
 endef
 TARGET_DEVICES += duzun_dm06
 
+define Device/elecom_wrc-1167fs
+  IMAGE_SIZE := 7360k
+  DEVICE_VENDOR := ELECOM
+  DEVICE_MODEL := WRC-1167FS
+  IMAGES += factory.bin
+  IMAGE/factory.bin := $$(sysupgrade_bin) | pad-to 64k | check-size | \
+	xor-image -p 29944A25 -x | elecom-header 00228000 | \
+	elecom-product-header WRC-1167FS
+  DEVICE_PACKAGES := kmod-mt76x2
+endef
+TARGET_DEVICES += elecom_wrc-1167fs
+
 define Device/glinet_gl-mt300n-v2
   IMAGE_SIZE := 16064k
   DEVICE_VENDOR := GL.iNet