New APIs for the wrapper funtions (VbSelectFirmware() and
VbSelectKernel()) and the APIs for the firmware services they need.
BUG=none
TEST=none
Change-Id: Id8ddc456d062095b12495dd534e21342b5490aee
Reviewed-on: http://gerrit.chromium.org/gerrit/2195
Reviewed-by: Gaurav Shah <gauravsh@chromium.org>
Tested-by: Randall Spangler <rspangler@chromium.org>