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/arch/x86/Kconfig

@@ -7,14 +7,6 @@ config X86_ARCH_OPTIONS
 	select HAVE_ARCH_MEMCPY
 	select HAVE_ARCH_MEMMOVE
 
-config MARK_GRAPHICS_MEM_WRCOMB
-	bool "Mark graphics memory as write-combining."
-	default n
-	help
-	 The graphics performance may increase if the graphics
-	 memory is set as write-combining cache type. This option
-	 enables marking the graphics memory as write-combining.
-
 # This is an SMP option. It relates to starting up APs.
 # It is usually set in mainboard/*/Kconfig.
 # TODO: Improve description.