[rbp/omxplayer] Support automatic deinterlace correctly.

Previously there was no distinction between deinterlace being automatic and force on.
Both did a hack parse that only worked (sometimes) for h264. Other codecs would always force on.

This change now handles the three modes correctly. Off and force on do as expected.
Automatic now queries the openmax video codec, which can reliably determine if a stream is interlaced