ALSA: usb-audio: Fix whitespace & blank line issues in mixer_quirks

Address all whitespace & blank line(s) related issues reported by
checkpatch.pl:

  ERROR: trailing whitespace
  ERROR: space required after that ',' (ctx:VxV)
  WARNING: Missing a blank line after declarations
  CHECK: Please use a blank line after function/struct/union/enum declarations
  CHECK: Please don't use multiple blank lines

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-v1-2-1a821463b632@collabora.com