travis: Adding RISC-V to the build.
travis: Adding RISC-V to the build.

timvideos/conda-hdmi2usb-packages,timvideos/conda-hdmi2usb-packages,timvideos/conda-misoc-lm32,litex-hub/litex-conda-compilers,timvideos/conda-misoc-lm32,litex-hub/litex-conda-eda,litex-hub/litex-conda-prog