PCI: Assign values to 'pci_obff_signal_type' enumeration constants

'pci_obff_signal_type' is passed between drivers and the kernel API.
This patch explicitly assigns values to the enumeration type's constants
which aids in detecting any future changes or additions that would break
the kernel's ABI.

No functional change.

Signed-off-by: Myron Stowe <myron.stowe@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

include/linux/pci.h

@@ -843,8 +843,8 @@ void pci_enable_ido(struct pci_dev *dev, unsigned long type);
 void pci_disable_ido(struct pci_dev *dev, unsigned long type);
 
 enum pci_obff_signal_type {
-	PCI_EXP_OBFF_SIGNAL_L0,
-	PCI_EXP_OBFF_SIGNAL_ALWAYS,
+	PCI_EXP_OBFF_SIGNAL_L0 = 0,
+	PCI_EXP_OBFF_SIGNAL_ALWAYS = 1,
 };
 int pci_enable_obff(struct pci_dev *dev, enum pci_obff_signal_type);
 void pci_disable_obff(struct pci_dev *dev);