[BUILD] Fix GCC warnning "no previous prototype".
[BUILD] Fix GCC warnning "no previous prototype".

- Set ARCONTROLLER_Stream2 local functions as static.

Change-Id: Ib4ce0b7e79afada0c0f5f578cc503d3841ffc389

Parrot-Developers/libARController,Parrot-Developers/libARController,Parrot-Developers/libARController,Parrot-Developers/libARController