Pin the kernel and initrd the riscv64 live image carries, that the kernel name
the other live images use is not accepted for it, and that the architecture the
media reports maps to riscv64 in both directions.
Signed-off-by: Vinícius Ferrão <2031761+viniciusferrao@users.noreply.github.com>
Pin both directions for every architecture xCAT supports on Ubuntu, the
pass-through for names Debian shares, and the round trip that copycd and
debootstrap depend on agreeing about.