arm64: dts: rockchip: rk3588: Add Edgeble Neu6 Model A SoM

Neural Compute Module 6(Neu2) is a 96boards SoM-CB compute module
based on Rockchip RK3588 from Edgeble AI.

General features:
- Rockchip RK3588
- up to 32GB LPDDR4x
- up to 128GB eMMC
- 2x MIPI CSI2 FPC

On module WiFi6/BT5 is available in the following Neu6 variants.

Neu6 needs to mount on top of associated Edgeble IO boards for
creating complete platform solutions.

Enable eMMC for now to boot Linux successfully.

commit <3d9a2f7e7c5e> ("arm64: dts: rockchip: rk3588: Add Edgeble Neu6
Model A SoM")

Add support for Edgeble Neu6 Model A SoM.

Signed-off-by: Jagan Teki <jagan@edgeble.ai>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>