removed type check in gpu::FarnebackOpticalFlow
removed type check in gpu::FarnebackOpticalFlow

now it supports all depths

opencv/opencv,opencv/opencv,apavlenko/opencv,opencv/opencv,apavlenko/opencv,opencv/opencv,apavlenko/opencv,apavlenko/opencv,apavlenko/opencv,opencv/opencv,opencv/opencv,apavlenko/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv