ppc: qemu: Enable VirtIO NET support

By default the QEMU ppce500 machine connects a VirtIO NET to the
PCI controller, although it can be replaced to an e1000 NIC via
additional command line options.

Now that we have switched over to DM PCI, VirtIO support becomes
possible. This commit enables the support.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
diff --git a/board/freescale/qemu-ppce500/qemu-ppce500.c b/board/freescale/qemu-ppce500/qemu-ppce500.c
index 79a6986..9c30c12 100644
--- a/board/freescale/qemu-ppce500/qemu-ppce500.c
+++ b/board/freescale/qemu-ppce500/qemu-ppce500.c
@@ -24,6 +24,8 @@
 #include <fdtdec.h>
 #include <errno.h>
 #include <malloc.h>
+#include <virtio_types.h>
+#include <virtio.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -130,6 +132,12 @@
 	if (ret)
 		return ret;
 
+	/*
+	 * Make sure virtio bus is enumerated so that peripherals
+	 * on the virtio bus can be discovered by their drivers.
+	 */
+	virtio_init();
+
 	return 0;
 }