Spotted this debugging OpenBSD's bootloader in qemu.  (Wouldn't really
fix anything, the problem was not having any disks, but we should
probably return the correct error code.)

Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>