faft: Refactor the one time setup methods of FAFT

This CL makes all the one time setup states in a single place. It'd be easy
to add more in the future. And wrap the class level variable in methods to
prevent mis-used.

BUG=chromium-os:34392
TEST=run a test suite to see the GBB flag setup only run once:
run_remote_tests.sh --board daisy --remote dut control.faft_lv1

Change-Id: I113cd04777231bbde8e3f924c0661b0412ac36ec
Reviewed-on: https://gerrit.chromium.org/gerrit/36303
Reviewed-by: Vic Yang <victoryang@chromium.org>
Commit-Ready: Tom Wai-Hong Tam <waihong@chromium.org>
Tested-by: Tom Wai-Hong Tam <waihong@chromium.org>
6 files changed