tty: serial: meson: Add a earlycon for the S4 SoC

The new Amlogic S4 SoC does not have a always-on uart, so add
OF_EARLYCON_DECLARE for it.
Amlogic T7 will use this as fallback.

Signed-off-by: Lucas Tanure <tanure@linux.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20231009121151.4509-1-tanure@linux.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>