pci: Add SRIOV helper function to determine if VFs are assigned to guest

This function is meant to add a helper function that will determine if a PF
has any VFs that are currently assigned to a guest.  We currently have been
implementing this function per driver, and going forward I would like to avoid
that by making this function generic and using this helper.

v2: Removed extern from declaration of pci_vfs_assigned in pci.h and return
    0 if SR-IOV is disabled with is inline with other PCI SRIOV functions.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 710067f..43e45ac 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1644,6 +1644,7 @@
 extern void pci_disable_sriov(struct pci_dev *dev);
 extern irqreturn_t pci_sriov_migration(struct pci_dev *dev);
 extern int pci_num_vf(struct pci_dev *dev);
+int pci_vfs_assigned(struct pci_dev *dev);
 extern int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs);
 extern int pci_sriov_get_totalvfs(struct pci_dev *dev);
 #else
@@ -1662,6 +1663,10 @@
 {
 	return 0;
 }
+static inline int pci_vfs_assigned(struct pci_dev *dev)
+{
+	return 0;
+}
 static inline int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs)
 {
 	return 0;