dts: add riscv include prefix link

The Allwinner D1/D1s SoCs (with a RISC-V core) use an (almost?) identical die as their R528/T113-s siblings with ARM Cortex-A7 cores. To allow sharing the basic SoC .dtsi files across those two architectures as well, introduce a symlink to the RISC-V DT directory.

APAndre Przywara committed 3 years ago