ALSA: usb-audio: add mapping for MSI MPG X570S Carbon Max Wifi.

[ Upstream commit 5762f980

 ]

The USB audio device 0db0:419c based on the Realtek ALC4080 chip exposes
all playback volume controls as "PCM". This is makes distinguishing the
individual functions hard.

The added mapping distinguishes all playback volume controls as their
respective function:
 - Speaker              - for back panel output
 - Frontpanel Headphone - for front panel output
 - IEC958               - for digital output on the back panel

This clarifies the individual volume control functions for users.

Signed-off-by: Johannes Schickel <lordhoto@gmail.com>
Link: https://lore.kernel.org/r/20220115140257.8751-1-lordhoto@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>