Generate GBB during factory instead of writing a prebuilt GBB.

Currently we need to prebuild GBBs off-line according to the values (HWID,
keys, and BMPFV) in component lists. During factory, it write the prebuilt
GBB to BIOS. This CL is to generate the GBB during factory, not need to
prebuild it.

TEST=run factory_WriteGBB in factory test and reboot to see change.

Review URL: http://codereview.chromium.org/3350021

Change-Id: I37bee5fbd1da56fa08682c2f7eff9f16bead9b4b
2 files changed