board: rockchip: Add FriendlyElec CM3588 NAS

The CM3588 NAS by FriendlyElec pairs the CM3588 compute module, based
on the Rockchip RK3588 SoC, with the CM3588 NAS Kit carrier board.

Features tested on a CM3588 NAS Kit with 8GB RAM 64GB eMMC module:
- SD-card boot
- eMMC boot
- Ethernet
- PCIe/NVMe
- USB gadget
- USB host

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
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