arm64: dts: axiado: Add initial support for AX3000 SoC and eval board

Add initial device tree support for the AX3000 SoC and its evaluation
platform. The AX3000 is a multi-core SoC featuring 4 Cortex-A53 cores,
Secure Vault, AI Engine and Firewall.

It adds support for Cortex-A53 CPUs, timer, UARTs, and I3C
controllers on the AX3000 evaluation board.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Harshit Shah <hshah@axiado.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>