ALSA: usb-audio: Fix block comments in mixer_quirks

Address a couple of comment formatting issues indicated by
checkpatch.pl:

  WARNING: Block comments use a trailing */ on a separate line

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20250526-dualsense-alsa-jack-v1-4-1a821463b632@collabora.com