virtio_pci: Introduce one new config api vp_get_vq_irq()

This config api is used to get irq of the given virtqueue.

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
virtio_net: Introduce one dummy function virtnet_filter_rfs()

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
virtio-net: Add accelerated RFS support

Accelerated RFS is used to select the RX queue.

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>