libpayload: cros: add serial number from coreboot table

Add serial number to lib_sysinfo from coreboot table.

BRANCH=none
BUG=chrome-os-partner:37813
TEST=ryu boots and /proc/device-tree/firmware/android is populated
with "compatible", "hardware", and "serialno" properties

Change-Id: I565b332a16b177c51907ffab7976ebd7a665aaaf
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 5535119f5d499b04bdc178c3040241d2872c4e13
Original-Change-Id: Ie2e222780d1577689a1cbf76ae8514c74fc469f4
Original-Signed-off-by: Stephen Barber <smbarber@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/259140
Original-Reviewed-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: http://review.coreboot.org/9881
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/payloads/libpayload/include/coreboot_tables.h b/payloads/libpayload/include/coreboot_tables.h
index c46fbf9..649cc2b 100644
--- a/payloads/libpayload/include/coreboot_tables.h
+++ b/payloads/libpayload/include/coreboot_tables.h
@@ -256,6 +256,9 @@
 	uint32_t erase_cmd;
 };
 
+#define CB_TAG_SERIALNO		0x002a
+#define CB_MAX_SERIALNO_LENGTH	32
+
 #define CB_TAG_CMOS_OPTION_TABLE 0x00c8
 struct cb_cmos_option_table {
 	u32 tag;