x86: chromebook_link: Implement CAR support (cache as RAM)

Add support for CAR so that we have memory to use prior to DRAM init.
On link there is a total of 128KB of CAR available, although some is
used for the memory reference code.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index aa7cf77..f27d731 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -34,6 +34,22 @@
 
 endchoice
 
+config RAMBASE
+	hex
+	default 0x100000
+
+config RAMTOP
+	hex
+	default 0x200000
+
+config XIP_ROM_SIZE
+	hex
+	default 0x10000
+
+config CPU_ADDR_BITS
+	int
+	default 36
+
 config ROM_SIZE
 	hex
 	default 0x800000