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/mainboard/intel/wtm2/Kconfig

@@ -14,7 +14,6 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select HAVE_SMI_HANDLER
 	select MAINBOARD_HAS_CHROMEOS
 	select CACHE_ROM
-	select MARK_GRAPHICS_MEM_WRCOMB
 	select MAINBOARD_HAS_NATIVE_VGA_INIT
 	select MONOTONIC_TIMER_MSR