[alsa-devel] usbaudio: Support for USB audio v2.0 devices

Here's a new version of the patchset to start support for USB audio v2.0 devices. I moved all the definitions to linux/usb/audio.h.

As I did that, I realized that there's actually many definitions in sound/usb/usbaudio.h which don't need to be there at all. Most of them are already defined in audio.h and ch9.h. Hence, I added a 5th patch to consolidate things and ease the chaos a bit. Hope I didn't break anything :)

Daniel