dt-bindings: riscv: Add Sipeed LicheeRV Nano board compatibles

dt-bindings: riscv: Add Sipeed LicheeRV Nano board compatibles

Document the compatible strings for the Sipeed LicheeRV Nano B board which
uses the SOPHGO SG2002 SoC.

Signed-off-by: Thomas Bonnefille <thomas.bonnefille@bootlin.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Inochi Amaoto <inochiama@outlook.com>
Link: https://lore.kernel.org/r/20240711-sg2002-v4-2-d97ec2367095@bootlin.com
Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
Signed-off-by: Chen Wang <unicorn_wang@outlook.com>