Vboot wrapper - add recovery reason, refactor timing

Pressing Tab at a firmware screen now displays real data, including
the recovery reason, HWID, and contents of VbNvStorage.

Entry point start/end time tracking in VbSharedData now refers to the
new wrapper APIs.

Added capability for calling firmware to request recovery mode (for
example, if it's unable to initialize RAM, can't find the SSD, etc.).
Previously, calling firmware had no (good) way to do this other than
faking the recovery button being pressed.

TEST=emerge on x86 and tegra2_seaboard

Change-Id: I7d377f279842b30a10d945d13571c41c464633f1
Reviewed-on: http://gerrit.chromium.org/gerrit/3814
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Randall Spangler <rspangler@chromium.org>
10 files changed