x86: Add chromebook_link board

This board is a 'bare' version of the existing 'link 'board. It does not
require coreboot to run, but is intended to start directly from the reset
vector.

This initial commit has place holders for a wide range of features. These
will be added in follow-on patches and series. So far it cannot be booted
as there is no ROM image produced, but it does build without errors.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/dts/Makefile b/arch/x86/dts/Makefile
index 48265ef..bb3b116 100644
--- a/arch/x86/dts/Makefile
+++ b/arch/x86/dts/Makefile
@@ -1,4 +1,5 @@
 dtb-y += link.dtb \
+	chromebook_link.dtb \
 	alex.dtb
 
 targets += $(dtb-y)