vboot2: misc higher-level routines

I'm breaking the last chunk of vboot2 into smaller pieces as I add
tests.  This has a bunch of misc routines like the dev switch logic
and GBB header parsing.

BUG=chromium:370082
BRANCH=none
TEST=make clean && VBOOT2=1 COV=1 make

Change-Id: I0f67400d9b59ec21ed5cc155a9b774fd37eb559b
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/203374
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
diff --git a/Makefile b/Makefile
index 2b5c1e2..d4d004d 100644
--- a/Makefile
+++ b/Makefile
@@ -322,6 +322,10 @@
 VBSLK_SRCS += \
 	firmware/stub/vboot_api_stub.c \
 	firmware/stub/vboot_api_stub_disk.c
+
+FWLIB2_SRCS += \
+	firmware/2lib/2stub.c
+
 endif
 
 VBSF_SRCS += ${VBINIT_SRCS}