The nvidia 375.xx driver introduces support for P016 output surfaces,
for 10bit and 12bit HEVC content (it's also the first driver to support
hardware decoding of 12bit content).

The cuvid api, as far as I can tell, only declares one output format
that they appear to refer to as P016 in the driver strings. Of course,
10bit content in P016 is identical to P010, and it is useful for
compatibility purposes to declare the format to be P010 to work with
other components that only know how to consume P010 (and to avoid
triggering swscale conversions that are lossy when they shouldn't be).

For simplicity, this change does not maintain the previous ability
to output dithered NV12 for 10/12 bit input video - the user will need
to update their driver to decode such videos.