mediatek: filogic: add support for Cudy WR3000P v1

mediatek: filogic: add support for Cudy WR3000P v1

Hardware
--------
MediaTek MT7981 WiSoC
512MB DDR4 RAM
128MB SPI-NAND
MediaTek MT7981 2x2 DBDC 802.11ax 2T2R (2.4 / 5)
4 LAN MediaTek MT7531 PHY
1 WAN RTL8221B-VB-CG 2.5Gbps PHY
UART: 115200 8N1 3.3V
USB2 Port
PoE on WAN Port

MAC:
LAN MAC: label mac
WAN MAC: label mac + 1
2.4G MAC: label mac
5G MAC: label mac + 1 with LA bit set

Gotchas:
WAN LED does not light up (might require further DTS tweaks)
PoE on WAN port was not tested

This commit is heavily based on WR3000H one, I've just ported DTS differences
from the official image to get USB support and proper LED mapping.

Installation
------------
[Untested as I've received and used a transitional image from Cudy]

1. Connect to the serial port as described in the "Hardware" section.

2. Power on the device + press reset pin. Keep pressing reset pin to enter the U-Boot  shell.

3. Download the OpenWrt initramfs image. Place it on an TFTP server
   connected to the Cudy LAN ports. Make sure the server is reachable at
   192.168.1.88. Rename the image to "cudy3000p.bin"

4. Download and boot the OpenWrt initramfs image.

   $ tftpboot 0x46000000 cudy3000s.bin; bootm 0x46000000

5. Transfer the OpenWrt sysupgrade image to the device using scp.
   Install with sysupgrade.

Signed-off-by: Michal Halva <hedik01@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/19636
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>