mc_tcu3: Enable the usage of blobs.

Since microcode was moved to 3rdparty/blobs, we need to select
USE_BLOBS in Kconfig to get the submodule 3rdparty/blobs automaticaly.

Change-Id: I25e574fd90b830448cacccd16d01a5a2dbc8517d
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: http://review.coreboot.org/11764
Tested-by: build bot (Jenkins)
Reviewed-by: Mario Scheithauer <mario.scheithauer@siemens.com>

src/mainboard/siemens/mc_tcu3/Kconfig

@@ -31,6 +31,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select TSC_MONOTONIC_TIMER
 	select DRIVER_INTEL_I210
 	select SOC_INTEL_FSP_BAYTRAIL_MD
+	select USE_BLOBS
 
 config MAINBOARD_DIR
 	string