netd: Add new flag for QCOM's hostap extension

 * Not everybody cares about this or needs it, so add a flag that can be
   used to include it for devices that include the full stack.

Change-Id: I66d217dec0553924e09592dd3162e930ecfe66fe
Merge remote-tracking branch 'CyanogenMod/cm-10.2' into cm-10.2