Add test to match struct device with pci_devfn_t

Add a function to test if pci_devfn_t matches with a device
instance of struct device, by comparing bus:dev.fn.

Change-Id: Ic6c3148ac62c7183246d83302ee504b17064c794
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/3474
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>

src/include/device/pci_def.h

@@ -474,4 +474,8 @@
 #define PCI_FUNC(devfn)		((devfn) & 0x07)
 #define PCI_BDF(bus,dev,func)	((bus) << 16 | (dev) << 11 | (func) << 8)
 
+/* Translation from PCI_DEV() to devicetree bus and path.pci.devfn. */
+#define PCI_DEV2DEVFN(sdev)		(((sdev)>>12) & 0xff)
+#define PCI_DEV2SEGBUS(sdev)	(((sdev)>>20) & 0xfff)
+
 #endif /* PCI_DEF_H */