PCI: hv: Document missing hv_pci_protocol_negotiation() parameter

Add missing documentation for the parameter "version" and "num_version"
of the hv_pci_protocol_negotiation() function and resolve build time
kernel-doc warnings:

  drivers/pci/controller/pci-hyperv.c:2535: warning: Function parameter
  or member 'version' not described in 'hv_pci_protocol_negotiation'

  drivers/pci/controller/pci-hyperv.c:2535: warning: Function parameter
  or member 'num_version' not described in 'hv_pci_protocol_negotiation'

No change to functionality intended.
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Link: https://lore.kernel.org/r/20200925234753.1767227-1-kw@linux.comReviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>

drivers/pci/controller/pci-hyperv.c

@@ -2515,7 +2515,10 @@ static void hv_pci_onchannelcallback(void *context)
 
 /**
  * hv_pci_protocol_negotiation() - Set up protocol
- * @hdev:	VMBus's tracking struct for this root PCI bus
+ * @hdev:		VMBus's tracking struct for this root PCI bus.
+ * @version:		Array of supported channel protocol versions in
+ *			the order of probing - highest go first.
+ * @num_version:	Number of elements in the version array.
  *
  * This driver is intended to support running on Windows 10
  * (server) and later versions. It will not run on earlier