ALSA: usb-audio: fix Corsair Virtuoso mixer label collision

The Corsair Virtuoso RGB Wireless is a USB headset with a mic and a
sidetone feature. Label its mixer appropriately instead of all
"Headset", so that applications such as Pulseaudio don't just move
the sidetone control when they intend the main Headset control.

Signed-off-by: Chris Boyle <chris@boyle.name>
Link: https://lore.kernel.org/r/20191227094053.GA12167@nova.chris.boyle.name


Signed-off-by: Takashi Iwai <tiwai@suse.de>