mb/biostar/th61-itx/early_init.c: Clean includes

Change-Id: I0619e567527812bd0e7088d23d91f114c8fec9ec
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50200
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/mainboard/biostar/th61-itx/early_init.c

@@ -1,9 +1,8 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
-#include <bootblock_common.h>
 #include <northbridge/intel/sandybridge/raminit_native.h>
-#include <northbridge/intel/sandybridge/sandybridge.h>
 #include <southbridge/intel/bd82x6x/pch.h>
+#include <stdbool.h>
 
 const struct southbridge_usb_port mainboard_usb_ports[] = {
 	{ 1, 0, 0 },