soc/intel/skylake: Add chipset devicetree

Set most of the devices to off to keep current behaviour.

Change-Id: Ic4dbd965c84c3679e42a181dea0e7e618c12fb97
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46314
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
diff --git a/src/soc/intel/skylake/Kconfig b/src/soc/intel/skylake/Kconfig
index ba3af84..314a08b 100644
--- a/src/soc/intel/skylake/Kconfig
+++ b/src/soc/intel/skylake/Kconfig
@@ -282,6 +282,10 @@
 	hex
 	default 0xc35
 
+config CHIPSET_DEVICETREE
+	string
+	default "soc/intel/skylake/chipset.cb"
+
 config IFD_CHIPSET
 	string
 	default "sklkbl"