google/banon: add new board as variant of cyan baseboard

Add support for google/banon (Acer Chromebook 15 CB3-531) as
a variant of the cyan Braswell baseboard.

- Add board-specific code as the new banon variant

Sourced from Chromium branch firmware-strago-7287.B,
commit 02dc8db: Banon: 2nd source DDR memory (Micro-MT52L256M32D1PF)

Change-Id: If29e95deee88b79522547e16fc80c2d5378da7c7
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/21571
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>
diff --git a/src/mainboard/google/cyan/Kconfig b/src/mainboard/google/cyan/Kconfig
index 650ef9a..0039f73 100644
--- a/src/mainboard/google/cyan/Kconfig
+++ b/src/mainboard/google/cyan/Kconfig
@@ -41,6 +41,7 @@
 
 config VARIANT_DIR
 	string
+	default "banon" if BOARD_GOOGLE_BANON
 	default "cyan" if BOARD_GOOGLE_CYAN
 	default "edgar" if BOARD_GOOGLE_EDGAR
 	default "reks" if BOARD_GOOGLE_REKS
@@ -48,6 +49,7 @@
 
 config MAINBOARD_PART_NUMBER
 	string
+	default "Banon" if BOARD_GOOGLE_BANON
 	default "Cyan" if BOARD_GOOGLE_CYAN
 	default "Edgar" if BOARD_GOOGLE_EDGAR
 	default "Reks" if BOARD_GOOGLE_REKS
@@ -59,6 +61,7 @@
 
 config DEVICETREE
 	string
+	default "variants/banon/devicetree.cb" if BOARD_GOOGLE_BANON
 	default "variants/cyan/devicetree.cb" if BOARD_GOOGLE_CYAN
 	default "variants/edgar/devicetree.cb" if BOARD_GOOGLE_EDGAR
 	default "variants/reks/devicetree.cb" if BOARD_GOOGLE_REKS
@@ -84,6 +87,7 @@
 config GBB_HWID
 	string
 	depends on CHROMEOS
+	default "BANON TEST A-A 8050" if BOARD_GOOGLE_BANON
 	default "CYAN TEST A-A 1829" if BOARD_GOOGLE_CYAN
 	default "EDGAR TEST A-A 2507" if BOARD_GOOGLE_EDGAR
 	default "REKS TEST A-A 3004" if BOARD_GOOGLE_REKS