google/kahlee: Save VBNV data to CMOS

Store VBOOT NV data in CMOS. This allows VBOOT to save flags and data
to be used in multiple stages and depthcharge. Fixes developer mode
USB boot.

Change-Id: I50b45e687a1a1c71838bcc390212b28d7e634a19
Signed-off-by: Marc Jones <marcj303@gmail.com>
Reviewed-on: https://review.coreboot.org/19847
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/mainboard/google/kahlee/Kconfig

@@ -54,6 +54,11 @@ config VBOOT
 	select VBOOT_MOCK_SECDATA
 	select EC_GOOGLE_CHROMEEC_SWITCHES
 	select VBOOT_LID_SWITCH
+	select VBOOT_VBNV_CMOS
+
+config VBOOT_VBNV_OFFSET
+	hex
+	default 0x2A
 
 config CHROMEOS
 	select LP_DEFCONFIG_OVERRIDE if PAYLOAD_DEPTHCHARGE

src/mainboard/google/kahlee/cmos.layout

@@ -58,6 +58,8 @@ entries
 440          4       e       9        slow_cpu
 444          1       e       1        nmi
 445          1       e       1        iommu
+#Used by ChromeOS:
+448        128       r       0        vbnv
 728        256       h       0        user_data
 984         16       h       0        check_sum
 # Reserve the extended AMD configuration registers