PCI: Add pci_probe_reset_slot() and pci_probe_reset_bus()

Users of pci_reset_bus() and pci_reset_slot() need a way to probe
whether the bus or slot supports reset.  Add trivial helper functions
and export them as vfio-pci will make use of these.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 1a8fd34..daf40cd 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -924,7 +924,9 @@
 int __pci_reset_function(struct pci_dev *dev);
 int __pci_reset_function_locked(struct pci_dev *dev);
 int pci_reset_function(struct pci_dev *dev);
+int pci_probe_reset_slot(struct pci_slot *slot);
 int pci_reset_slot(struct pci_slot *slot);
+int pci_probe_reset_bus(struct pci_bus *bus);
 int pci_reset_bus(struct pci_bus *bus);
 void pci_reset_bridge_secondary_bus(struct pci_dev *dev);
 void pci_update_resource(struct pci_dev *dev, int resno);