alsa-mixer: Add EPOS/Sennheiser GSP 670 and GSA 70
Add EPOS/Sennheiser GSP 670 headset and GSA 70 dongle (with and without updated firmware) as USB gaming headset.
Fixes #938 (closed)
Add EPOS/Sennheiser GSP 670 headset and GSA 70 dongle (with and without updated firmware) as USB gaming headset.
Fixes #938 (closed)