Enable distro boot on the qemu-riscv32/64 boards. Supported boot target
devices are VirtIO and DHCP.
Signed-off-by: NLukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: NBin Meng <bmeng.cn@gmail.com>
Reviewed-by: NAlexander Graf <agraf@suse.de>