Not all QEMU machines (outside of those available in OE-Core) are
capable of using the virtio-rng-pci device due to various machine models
not having a pci/virtio bus. This makes it such that the use of the
'-device virtio-rng-pci' flag to QEMU is machine specific.
This patch removes the general addition of the flag to all runqemu
targets and adds the flag into the QB_OPT_APPEND for all the qemu*
machines in OE-Core that support its use (which is all of them).
Signed-off-by: Nathan Rossi <nathan@nathanrossi.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
