ucm2: USB-Audio: Add Yamaha ZG02 profile (0499:1516)

[GitHub pull_request - opened <github@alsa-project.org>]

alsa-project/alsa-ucm-conf pull request #903 was opened from Z3dan:

Adds a UCM profile for the Yamaha ZG02 game streaming mixer, splitting its
10-channel playback and 4-channel capture streams into the mixer's buses:

| Stream | Channels | Device | Notes |
|---|---|---|---|
| Playback | 0–1 | Chat | follows the voice chat level knob |
| Playback | 2–9 | Game | 7.1, follows the game sound level knob |
| Capture | 0–1 | Streaming Mix | game + chat + mic, for streaming software |
| Capture | 2–3 | Microphone | headset/mic input only |

### How the mapping was verified

- **Playback:** sent audio to each channel pair in turn and turned each knob
  on the mixer down to see which pairs it controls.
- **Capture:** pressed the mixer's mic mute (capture 2–3 go digitally silent)
  while playing audio to Game and Chat (both show up on capture 0–1).
- The profile parses with `alsaucm dump` against the device. It has **not**
  been tested end to end in PipeWire yet.

### Kernel dependency

The ZG02 needs a kernel quirk to expose its PCM streams at all: "ALSA:
usb-audio: Add quirk for Yamaha ZG02", sent to linux-sound. Link:
https://lore.kernel.org/all/20261104-yamaha-zg02-v1-1-3fd61b8c564f@gmail.com/

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Request URL   : https://github.com/alsa-project/alsa-ucm-conf/pull/903
Patch URL     : https://github.com/alsa-project/alsa-ucm-conf/pull/903.patch
Repository URL: https://github.com/alsa-project/alsa-ucm-conf