riscv: include cross compilers in c10s builder container images
<span class="gl-align-middle -gl-mr-2 has-tooltip" title="The source project is a fork"><svg class="s12 gl-ml-1 has-tooltip" data-testid="fork-icon"><use href="/assets/icons-41229992eca580608aadaaa9b83b717650b2863442574d0ebb87f859c42a3b6c.svg#fork"></use></svg></span> mh21_rh/containers:riscv-include-cross-compilers-in-c10s into main