ALSA: scarlett2: Define autogain status texts per-config-set

The autogain status texts are different for Vocaster vs. Scarlett 4th
Gen, so make them configurable per-config-set.

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Message-ID: <b1adcd3dc48117d4ebe16812eeb7f1dbf1ede472.1710264833.git.g@b4.vu>