ALSA: usb-audio: Fix Audio Advantage Micro II SPDIF switch

commit a9224f26b754b5034719248891ff3c2ea0d11144 upstream.

snd_microii_spdif_switch_put() returns 0 when the requested
vendor register value differs from the cached one.

This comparison was inverted by the resume-support conversion,
so real SPDIF switch toggles are ignored while no-op writes still
issue SET_CUR and report success.

Return early only when the requested value matches the cached one.

Fixes: 288673beae ("ALSA: usb-audio: Add resume support for MicroII SPDIF ctls")
Cc: stable@vger.kernel.org
Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Link: https://patch.msgid.link/20260421-microii-spdif-switch-fix-v1-1-5c50dc28b88f@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ulrich Hecht <uli@kernel.org>

sound/usb/mixer_quirks.c

@@ -1936,7 +1936,7 @@ static int snd_microii_spdif_switch_put(struct snd_kcontrol *kcontrol,
 	int err;
 
 	reg = ucontrol->value.integer.value[0] ? 0x28 : 0x2a;
-	if (reg != list->kctl->private_value)
+	if (reg == list->kctl->private_value)
 		return 0;
 
 	kcontrol->private_value = reg;