virtio_pci: Fix misleading comment for queue vector

This patch fixes misleading comments in both legacy and modern
virtio-pci device implementations. The comments previously referred to
the "config vector" for parameters and return values of the
`vp_legacy_queue_vector()` and `vp_modern_queue_vector()` functions,
which is incorrect.

Signed-off-by: Liming Wu <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Michael S. Tsirkin <[e-mail]>

drivers/virtio/virtio_pci_legacy_dev.c

···
  * vp_legacy_queue_vector - set the MSIX vector for a specific virtqueue
  * @ldev: the legacy virtio-pci device
  * @index: queue index
- * @vector: the config vector
+ * @vector: the queue vector
  *
- * Returns the config vector read from the device
+ * Returns the queue vector read from the device
  */
 u16 vp_legacy_queue_vector(struct virtio_pci_legacy_device *ldev,
 			   u16 index, u16 vector)

drivers/virtio/virtio_pci_modern_dev.c

···
  * vp_modern_queue_vector - set the MSIX vector for a specific virtqueue
  * @mdev: the modern virtio-pci device
  * @index: queue index
- * @vector: the config vector
+ * @vector: the queue vector
  *
- * Returns the config vector read from the device
+ * Returns the queue vector read from the device
  */
 u16 vp_modern_queue_vector(struct virtio_pci_modern_device *mdev,
 			   u16 index, u16 vector)