MTRR: Mark all prefetchable resources as WRCOMB.

Change-Id: I2ecfd9733b65b6160bc2232d22db7b16692a847f
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/5149
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>

src/northbridge/intel/nehalem/gma.c

@@ -703,9 +703,6 @@ static void gma_read_resources(struct device *dev)
 			   0xd0000001);
 	pci_write_config32(dev, PCI_BASE_ADDRESS_2 + 4,
 			   0);
-#if CONFIG_MARK_GRAPHICS_MEM_WRCOMB
-	res->flags |= IORESOURCE_WRCOMB;
-#endif
 	res->base = (resource_t) 0xd0000000;
 	res->size = (resource_t) 0x10000000;
 }