camera: allow disabling zsl for ffc

* jf needs this for ffc video recording on snapchat
* snapchat does not send the recording hint, so we need to just
  disable it altogether on ffc

Change-Id: I777f2bb805e6c6f61638201615755fb14a00387e
Merge "camera: allow disabling zsl for ffc" into cm-11.0
Merge branch 'cm' into HEAD