Add BOOT_TARGET to hnvram lib.

This is change 1/2 that allows the userspace
hnvram command to r/w BOOT_TARGET.

Change-Id: Ia584337065b377f66393f75fe17dda2b9942777f
(cherry picked from commit bec1407b0ef47dbc93ca6c97e3abe272eeae06f3)
2 files changed
tree: 6a36c2560aec86d8dfd58e29ef790e5a5933c1d9
  1. libupgrade/
  2. makehdf