Camera2: Add PASSIVE_UNFOCUSED autofocus state.

The AF state model didn't properly account for the AF algorithm giving
up focusing while in passive scan, which leads to bad state
information being given to the application. Add this state to clarify.

Also a few minor comment edits from the autogeneration.

Bug: 10860639
Change-Id: Ib6b781fb8222a2c06dbc89b7496c593ac87cc026