[coreboot] Scan-build errors

[Myles Watson]

It looks like many of the scan-build errors are because of missing
defines.  It doesn't look like scan-build is seeing settings.h.  Would
that be easy to fix? I think if we remove some of the noise it will be
more useful.

Here's an example from:
http://coresystems.de/~stepan/coreboot-scanbuild/tyan_s2892-scanbuild/failures/clang_parser_rejects_0rrJqa.i.stderr.txt

/home/stepan/svn/scan-build/coreboot-v2//src/devices/pci_device.c:600:3:
error: use of undeclared identifier
'MAINBOARD_PCI_SUBSYSTEM_VENDOR_ID'
                printk_debug("%s subsystem <- %02x/%02x\n",
                ^
/home/stepan/svn/scan-build/coreboot-v2//src/devices/pci_device.c:602:4:
note: instantiated from:
                        MAINBOARD_PCI_SUBSYSTEM_VENDOR_ID,
                        ^
/home/stepan/svn/scan-build/coreboot-v2//src/devices/pci_device.c:605:4:
error: use of undeclared identifier
'MAINBOARD_PCI_SUBSYSTEM_VENDOR_ID'
                        MAINBOARD_PCI_SUBSYSTEM_VENDOR_ID,
                        ^

Thanks,
Myles