PCI/x86: make early dump handle multi-function devices

The early "dump PCI config space" code skips many multi-function
devices.  This patch fixes that, so it dumps all devices in PCI
domain 0.

We should not skip the rest of the functions if CLASS_REVISION is
0xffffffff.  Often multi-function devices have gaps in the function ID
space, e.g., 1c.0 and 1c.2 exist but 1c.1 doesn't.  The CLASS_REVISION
of the non-existent 1c.1 function will appear to be 0xffffffff.

We should only look at the HEADER_TYPE of function zero.  Often the
"multi-function" is set in function zero, but not in other functions.
Signed-off-by: NBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

arch/x86/pci/early.c

@@ -96,18 +96,21 @@ void early_dump_pci_devices(void)
 			for (func = 0; func < 8; func++) {
 				u32 class;
 				u8 type;
+
 				class = read_pci_config(bus, slot, func,
 							PCI_CLASS_REVISION);
 				if (class == 0xffffffff)
-					break;
+					continue;
 
 				early_dump_pci_device(bus, slot, func);
 
-				/* No multi-function device? */
-				type = read_pci_config_byte(bus, slot, func,
+				if (func == 0) {
+					type = read_pci_config_byte(bus, slot,
+								    func,
 							       PCI_HEADER_TYPE);
-				if (!(type & 0x80))
-					break;
+					if (!(type & 0x80))
+						break;
+				}
 			}
 		}
 	}