winks: performance improvements

* Make the driver write directly into each GstBuffer to avoid memcpy().
* Don't memset() the buffer before reusing it.
* Recycle memory by keeping two spare buffers. Two because the sink
  downstream may keep a ref to the previous buffer.

Note that we align buffers on highest possible byte boundary (4096) so we
don't have to take into account what kind of alignment the driver requires.
3 files changed