PCI-IOV: fix missing kernel-doc

Fix PCI iov kernel-doc warning:

Warning(drivers/pci/iov.c:638): No description found for parameter 'nr_virtfn'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 7227efc7..b497daa 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -631,6 +631,7 @@
 /**
  * pci_enable_sriov - enable the SR-IOV capability
  * @dev: the PCI device
+ * @nr_virtfn: number of virtual functions to enable
  *
  * Returns 0 on success, or negative on failure.
  */