ARM: dts: sun8i: s3: Add dtsi for the Elimo Impetus SoM

The Elimo Engineering Impetus is an Open Source Hardware System-on-Module
based on the SoChip S3 SoC.

It is meant for integration into carrier boards or, more generally,
larger designs, and uses an M2 connector to facilitate that.

Interfaces on the M.2/NGFF 42mm connector:
WiFi IEEE 802. 11abgn (on-module Realtek)
Bluetooth 4.2/BLE (on-module Realtek)
RGB LCD Interface (on-module connector)
MIPI Camera Interface (on-module connector)
IEEE 802. 3u Ethernet MAC (external connecto)
USB2.0 (Host, Device, OTG) (external connector)
Audio Line In/Out (external connector)

Signed-off-by: Matteo Scordino <matteo.scordino@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20201105183231.12952-2-matteo.scordino@gmail.com