mb/siemens/chili: Introduce include folder for header files

Use include folder for header files allowing proper includes.

Change-Id: I80066fb925b918d040062397e633c5d499a50dbe
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47973
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/siemens/chili/Makefile.inc

@@ -1,6 +1,6 @@
 ## SPDX-License-Identifier: GPL-2.0-only
 
-CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)
+CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
 
 romstage-y += romstage.c
 

src/mainboard/siemens/chili/ec.c

@@ -4,10 +4,9 @@
 #include <console/console.h>
 #include <cpu/x86/smm.h>
 #include <ec/acpi/ec.h>
+#include <mainboard/ec.h>
 #include <timer.h>
 
-#include "ec.h"
-
 #define EC_STATUS			0x50
 #define   EC_RUNNING			(1 << 1)
 #define EC_DEVICE_CONTROL_1		0x80

src/mainboard/siemens/chili/mainboard.c

@@ -1,8 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <device/device.h>
-
+#include <mainboard/ec.h>
-#include "ec.h"
 
 static void mainboard_dev_init(struct device *dev)
 {

src/mainboard/siemens/chili/romstage.c

@@ -4,8 +4,7 @@
 #include <soc/cnl_memcfg_init.h>
 #include <soc/gpio.h>
 #include <soc/romstage.h>
-
+#include <variant.h>
-#include "variant.h"
 
 static void mainboard_init(void)
 {

src/mainboard/siemens/chili/variants/base/gpio.c

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <soc/gpio.h>
-#include "variant.h"
+#include <variant.h>
 
 static const struct pad_config gpio_table[] = {
 /* GPP_A14  GPIO                  */ PAD_NC(GPP_A14, NONE),

src/mainboard/siemens/chili/variants/chili/gpio.c

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <soc/gpio.h>
-#include "variant.h"
+#include <variant.h>
 
 static const struct pad_config gpio_table[] = {
 /* GPP_A14   GPIO                 0x0000002644000300 */ PAD_NC(GPP_A14, NONE),

src/mainboard/siemens/chili/variants/chili/romstage.c

@@ -3,8 +3,7 @@
 #include <option.h>
 #include <console/console.h>
 #include <fsp/soc_binding.h>
-
+#include <variant.h>
-#include "../../variant.h"
 
 void variant_romstage_params(FSPM_UPD *const mupd)
 {