mc_tcu3: Enable graphic init code

The used Baytrail-M SoC on TCU3 tend to have issues
with DisplayPort if the graphic power gate is not set up
in coreboot. To avoid this error, use the graphic init
code on this board.

Change-Id: I973bbaa7d86c1ede1f2884b3a08ccb31f7d85087
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/13774
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

src/mainboard/siemens/mc_tcu3/Kconfig

@@ -29,6 +29,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select SOC_INTEL_FSP_BAYTRAIL_MD
 	select USE_BLOBS
 	select CBFS_AUTOGEN_ATTRIBUTES
+	select FSP_BAYTRAIL_GFX_INIT
 
 config MAINBOARD_DIR
 	string