dt-bindings: riscv: Add Anlogic DR1V90

dt-bindings: riscv: Add Anlogic DR1V90

Add Anlogic DR1V90 FPSoC, featuring a UX900 RISC-V core as the
processing system (PS) and 94,464 LUTs programmable logic (PL). It is
used by the Milianke MLKPAI-FS01 board, a SBC equipped with 512MB DDR3
memory, USB-C UART, 1GbE RJ45 Ethernet, USB-A 2.0 port, TF card slot,
and 256Mbit Quad-SPI flash.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Junhui Liu <junhui.liu@pigmoral.tech>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>