Consolidate intel vga int15 hooks

Change-Id: I9366dded98bf15f6da44ce893dd10698ba09fd55
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/6820
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>

src/mainboard/intel/wtm2/Kconfig

@@ -14,6 +14,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select MAINBOARD_HAS_CHROMEOS
 	select MAINBOARD_HAS_NATIVE_VGA_INIT
 	select MONOTONIC_TIMER_MSR
+	select INTEL_INT15
 
 config MAINBOARD_DIR
 	string