virtio-net: use qemu_get_queue() where possible

qemu_get_queue() is a shorthand for qemu_get_subqueue(n->nic, 0).  Use
the shorthand where possible.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

hw/net/virtio-net.c

@@ -459,7 +459,7 @@ static uint32_t virtio_net_bad_features(VirtIODevice *vdev)
 
 static void virtio_net_apply_guest_offloads(VirtIONet *n)
 {
-    qemu_set_offload(qemu_get_subqueue(n->nic, 0)->peer,
+    qemu_set_offload(qemu_get_queue(n->nic)->peer,
             !!(n->curr_guest_offloads & (1ULL << VIRTIO_NET_F_GUEST_CSUM)),
             !!(n->curr_guest_offloads & (1ULL << VIRTIO_NET_F_GUEST_TSO4)),
             !!(n->curr_guest_offloads & (1ULL << VIRTIO_NET_F_GUEST_TSO6)),