g2: Change /dev/diag ownership to radio:radio

In order to log vendor RIL logs, diag must have radio permissions.
diag shouldn't world readable.

Change-Id: Ic872ae1a24accac330bde5f2338bb1a3d74230d6
Enable NEEDS_VECTORIMPL_SYMBOLS which is needed for the blobs.
Fixes camera after Dhackers core merge.