x86, mrst: Don't blindly access extended config space

Do not blindly access extended configuration space unless we actively
know we're on a Moorestown platform.  The fixed-size BAR capability
lives in the extended configuration space, and thus is not applicable
if the configuration space isn't appropriately sized.

This fixes booting certain VMware configurations with CONFIG_MRST=y.

Moorestown will add a fake PCI-X 266 capability to advertise the
presence of extended configuration space.
Reported-and-tested-by: Petr Vandrovec <petr@vandrovec.name>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Acked-by: Jacob Pan <jacob.jun.pan@intel.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
LKML-Reference: <AANLkTiltKUa3TrKR1M51eGw8FLNoQJSLT0k0_K5X3-OJ@mail.gmail.com>

arch/x86/pci/mrst.c

@@ -247,6 +247,10 @@ static void __devinit pci_fixed_bar_fixup(struct pci_dev *dev)
 	u32 size;
 	int i;
 
+	/* Must have extended configuration space */
+	if (dev->cfg_size < PCIE_CAP_OFFSET + 4)
+		return;
+
 	/* Fixup the BAR sizes for fixed BAR devices and make them unmoveable */
 	offset = fixed_bar_cap(dev->bus, dev->devfn);
 	if (!offset || PCI_DEVFN(2, 0) == dev->devfn ||