ALSA: usb-audio: separate DJM-A9 cap lvl options

ALSA: usb-audio: separate DJM-A9 cap lvl options

Mixer quicks for the Pioneer DJM-A9 mixer was added in 5289d00 with
additional capture level values added to the common DJM array of values.

This breaks the existing DJM mixers however as alsa-utils relies on
enumeration of the actual mixer options based on the value array which
results in error when storing state.

This commit just separates the A9 values into a separate array and
references them in the corresponding mixer control.

Fixes: 5289d0069639 ("ALSA: usb-audio: Add Pioneer DJ/AlphaTheta DJM-A9 Mixer")
Signed-off-by: Olivia Mackintosh <livvy@base.nu>
Link: https://patch.msgid.link/20250316153323.16381-1-livvy@base.nu
Signed-off-by: Takashi Iwai <tiwai@suse.de>