USB MIDI: Only use first USB Configuration

The parser returns USB descriptors for multiple configurations.
Only one configuration should be used at once.
The first configuration is the default config.

Bug: 234607936
Bug: 223316278
Test: CTS Verifier on AudioBox 96
Test: MIDI Scope on MIDI 2.0 device
Change-Id: I9169faa2ea5cf9fd516834f7802963245762e74b