Better wifi-enabled signal from network controller.

The old "is wifi enabled" signal was geared toward the cluster
view.  Since the clients of the callbacks are now only QS tiles,
make sure to plumb through the actual enabled value all the way
up to the tile.

Bug:15161053
Change-Id: I8b69c599f06d5b36e3f44dc666e1621840ffd927
(cherry picked from commit fd0ea545d47b19c2ebff203a6e768a60698f3609)