virtio_pci: use helper function is_power_of_2()

Use helper function is_power_of_2() to check if num is power of two.
Minor readability improvement.
Signed-off-by: Shaoqin Huang <shaoqin.huang@intel.com>
Message-Id: <20221021062734.228881-2-shaoqin.huang@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>

drivers/virtio/virtio_pci_modern.c

@@ -310,7 +310,7 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 	if (!num || vp_modern_get_queue_enable(mdev, index))
 		return ERR_PTR(-ENOENT);
 
-	if (num & (num - 1)) {
+	if (!is_power_of_2(num)) {
 		dev_warn(&vp_dev->pci_dev->dev, "bad queue size %u", num);
 		return ERR_PTR(-EINVAL);
 	}