SPA_POD_CHOICE_ENUM_Int must always take at least 2 values as first one
is default. (Just 1 value no longer works on current master, and it's
anyway incorrect.)
Replace with just SPA_POD_Int, as there's just one choice.
LC3 and Opus have built-in support for packet loss concealment.
Add codec interface for that, and implement for LC3.
Extend media_codec interface so that packets not aligned with socket
reads can be handled, as in HFP. This is required for correct sequence
number counting, and for being able to run codec PLC *before* decoding
the next correctly received packet.
