arm64: dts: add support for C3 based Amlogic AW409

Amlogic C3 is an advanced edge AI processor designed for smart IP camera
applications.

Add basic support for the C3 based Amlogic AW409 board, which describes
the following components: CPU, GIC, IRQ, Timer, UART. It's capable of
booting up into the serial console.

Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
Link: https://lore.kernel.org/r/20230515093237.2203171-1-xianwei.zhao@amlogic.com


Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>