riscv: dts: sophgo: Add LicheeRV Nano board device tree

riscv: dts: sophgo: Add LicheeRV Nano board device tree

LicheeRV Nano B [1] is an embedded development platform based on the SOPHGO
SG2002 chip, the B(ase) version is deprived of Wifi/Bluetooth and Ethernet.

Add only support for UART and SDHCI.

Link: https://wiki.sipeed.com/hardware/en/lichee/RV_Nano/1_intro.html
Signed-off-by: Thomas Bonnefille <thomas.bonnefille@bootlin.com>
Reviewed-by: Inochi Amaoto <inochiama@gmail.com>
Link: https://lore.kernel.org/r/20241010-sg2002-v5-2-a0f2e582b932@bootlin.com
Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Signed-off-by: Chen Wang <unicorn_wang@outlook.com>