ARM: dts: Introduce the NXP LS1021A-TSN board

The LS1021A-TSN is a development board built by VVDN/Argonboards in
partnership with NXP.

It features the LS1021A SoC and the first-generation SJA1105T Ethernet
switch for prototyping implementations of a subset of IEEE 802.1 TSN
standards.

It has two regular Ethernet ports and four switched, TSN-capable ports.

It also features:
- One Arduino header
- One expansion header
- Two USB 3.0 ports
- One mini PCIe slot
- One SATA interface
- Accelerometer, gyroscope, temperature sensors

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>