Camera2: enable antibanding by default

The default for antibanding should be "auto", otherwise there will
be banding effect when taking photos in certain lighting.

Normally, the default on most devices is "auto" (depends on Camera
HAL). But the code from CAF changed it so that the Camera app
explicitly change it to "off".

Change-Id: I3f1576ef85117ddb653816f48437eb7dc8b83b39