riscv: hwprobe: export Zicond extension

Export the zicond extension to userspace using hwprobe.

Signed-off-by: Clément Léger <cleger@rivosinc.com>
Link: https://lore.kernel.org/r/20231220155723.684081-7-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>