arm64: dts: rockchip: Add Radxa CM3J on RPi CM4 IO Board

arm64: dts: rockchip: Add Radxa CM3J on RPi CM4 IO Board

The Raspberry Pi Compute Module 4 IO Board is an application board for
the Compute Module 4. [1]

This patch adds support for the Radxa CM3J mounted on the RPi CM4 IO
Board.

Specification:
- 12V 5521 DC jack
- 2x full-size HDMI 2.0 connectors (only HDMI0 is supported with CM3J)
- Gigabit Ethernet RJ45 with PoE support
- 2x USB 2.0 connectors, with header for two more connectors
- Micro USB connector
- microSD card socket
- PCIe Gen 2 x1 socket
- 12V 4-pin PWM fan connector
- External power connector (+5V, +12V)
- 2x MIPI DSI connectors
- 2x MIPI CSI-2 connectors
- 40-pin GPIO header
- RTC with battery socket
- Red (power) and green (heartbeat) LEDs

[1] https://datasheets.raspberrypi.com/cm4io/cm4io-datasheet.pdf

Signed-off-by: FUKAUMI Naoki <naoki@radxa.com>
Link: https://patch.msgid.link/20260108113341.14037-3-naoki@radxa.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>