ARM: dts: sun8i: s3: Add dts for the Elimo Initium SBC

The Elimo Engineering Initium is an Open Source Hardware Single Board
Computer based on the Elimo Impetus SoM.

It is meant as the first development platform for the Impetus, providing
convenient access to the peripherals on the Impetus.

It provides:
USB-C power input
UART-to-USB bridge on the USB-C connector, connected to UART1
USB-A connector for USB2.0 (Host, Device, OTG)
Audio Line In/Out
Pin header to access all signals on the M2 connector of the SoM

Signed-off-by: Matteo Scordino <matteo.scordino@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20201105183231.12952-4-matteo.scordino@gmail.com