Some improvements that make playback mostly reliable for me - the final
piece of the jigaw is probably in vchiq:

- prefill vchiq with a number (currently 2) blocks of audio before
  starting

- use a kthread as workqueue isn't suited to our usage.

- don't drain on stopping as for some reason it leaves data behind.
 Add some devices. Not tested because I have no any of these devices/cards.
- Add some PCI subclass and interfaces.
- The interface of PCI_SUBCLASS_BRIDGE_RACEWAY is not decoded yet.
- Fix typo in a message.
- Add comment.
- Modify comment.
 Delete 82580ER related code. It was from FreeBSD and was removed in r203049.
Fix debug message.
s/genric/generic/