mediatek: add cudy wr3000h-v1 ubootmod

mediatek: add cudy wr3000h-v1 ubootmod

This allows us to use the full size of nand,
which extends ubi size from 64Mb to 122.25Mb.

1. Log in to the device and backup all the partitions,
especially unique "Factory" and "bdata" partitions
from System -> Backup / Flash Firmware -> Save mtdblock contents.
2. Install kmod-mtd-rw to unlock mtd partitions for writing
  apk update && apk add kmod-mtd-rw && insmod mtd-rw i_want_a_brick=1

3. Write new OpenWrt (U-Boot Layout) "BL2" and "FIP":
  mtd -e BL2 write openwrt-mediatek-filogic-cudy_wr3000h-v1-ubootmod-preloader.bin BL2
  mtd -e FIP write openwrt-mediatek-filogic-cudy_wr3000h-v1-ubootmod-bl31-uboot.fip FIP
4. Set static IP on your PC: "192.168.1.254", gateway "192.168.1.1"
5. Serve openwrt-mediatek-filogic-cudy_wr3000h-v1-ubootmod-initramfs-recovery.itb
using TFTP server.
6. Connect Router LAN with PC LAN.
7. Cut off the power and re-engage, wait for TFTP recovery to complete.
8. After OpenWrt initramfs recovery has booted,
clean "/dev/mtd5" ubi partition to utilize maximum of free space:
  ubidetach -p /dev/mtd5; ubiformat /dev/mtd5 -y; ubiattach -p /dev/mtd5
  ubimkvol /dev/ubi0 -n 0 -N ubootenv -s 128KiB
  ubimkvol /dev/ubi0 -n 1 -N ubootenv2 -s 128KiB
9. Perform sysupgrade.

Signed-off-by: Dmitry Mostovoy <stavultras@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/21943
Signed-off-by: Robert Marko <robimarko@gmail.com>