ALSA: scarlett2: Rename Gen 3 config sets

The config sets are named NO_MIXER, GEN_2, GEN_3, and CLARETT
currently. Rename NO_MIXER and GEN_3 to GEN_3A and GEN_3B respectively
as NO_MIXER is only for the smaller Gen 3 devices.

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Link: https://lore.kernel.org/r/19ae5eea7fc499945efa8eeda7fcd8afe73f62d9.1698342632.git.g@b4.vu


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