virtio: pci: Support non-legacy PCI transport device

By default QEMU creates legacy PCI transport devices, but we can
ask QEMU to create non-legacy one if we pass additional device
property/value pairs in the command line:

  -device virtio-blk-pci,disable-legacy=true,disable-modern=false

This adds a new driver driver to support non-legacy (modern) device
mode. Previous driver/file name is changed accordingly.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile
index 5ee6183..072fb56 100644
--- a/drivers/virtio/Makefile
+++ b/drivers/virtio/Makefile
@@ -5,6 +5,6 @@
 
 obj-y += virtio-uclass.o virtio_ring.o
 obj-$(CONFIG_VIRTIO_MMIO) += virtio_mmio.o
-obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o
+obj-$(CONFIG_VIRTIO_PCI) += virtio_pci_legacy.o virtio_pci_modern.o
 obj-$(CONFIG_VIRTIO_NET) += virtio_net.o
 obj-$(CONFIG_VIRTIO_BLK) += virtio_blk.o