tests: add camera input for encode

add id in VideoEncRawBuffer for camera buffer recycle
tests: use camera input in h264encode test

./h264encode -i /dev/video0 -s YUY2 -W 640 -H 480 -c AVC -o out.h264  && ./decode -i out.h264
tests/v4l2: use EncodeStreamInput(including camera) in v4l2encode test

improve EncodeStreamInputFile accept 'userptr' mode:
copy data into giving buffer (since v4l2encode input buffer can't be
recycled immediately)