Bootctrl: Supporting bootctrl on HQX. [part 2...]

1. Updating get_number_slots API, to return 2 on HQX
2. Updating set_active_boot_slot API, write current, target slot,
   status of target slot info into la_misc partition, which will
   read by PVM during slot switching and OTA update.

Change-Id: If171ac32e30fcaf17b079e1c9f3465ff236dc7c8
2 files changed