Amlogic A4 is an application processor designed for smart audio
and IoT applications.

Add basic support for the A4 based Amlogic BA400 board, which describes
the following components: CPU, GIC, IRQ, Timer and UART.
These are capable of booting up into the serial console.
Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240401-basic_dt-v3-4-cb29ae1c16da@amlogic.comSigned-off-by: Neil Armstrong <neil.armstrong@linaro.org>