PCI: Use u8, not int, for PM capability offset

The Power Management Capability (PCI_CAP_ID_PM == 0x01) is defined by PCI
and must appear in the 256-byte PCI Configuration Space from 0-0xff.  It
cannot be in the PCIe Extended Configuration space from 0x100-0xfff, so
we only need a u8 to hold its offset.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

include/linux/pci.h

@@ -249,8 +249,7 @@ struct pci_dev {
 	pci_power_t     current_state;  /* Current operating state. In ACPI-speak,
 					   this is D0-D3, D0 being fully functional,
 					   and D3 being off. */
-	int		pm_cap;		/* PM capability offset in the
-					   configuration space */
+	u8		pm_cap;		/* PM capability offset */
 	unsigned int	pme_support:5;	/* Bitmask of states from which PME#
 					   can be generated */
 	unsigned int	pme_interrupt:1;