fix todo for 15 fps mode on r200
fix todo for 15 fps mode on r200

IntelRealSense/librealsense,floe/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,floe/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,floe/librealsense,IntelRealSense/librealsense