riscv: dts: canaan: add specific compatible for kd233's LCD

Add the recently introduced compatible for the LCD on the Canaan KD233.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20220705215213.1802496-13-mail@conchuod.ie


Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>