ALSA: usb-audio: scarlett2: Fix scarlett2_*_ctl_put() return values

Mixer control put callbacks should return 1 if the value is changed.
Fix the sw_hw, level, pad, and button controls accordingly.
Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Link: https://lore.kernel.org/r/20210620164645.GA9221@m.b4.vuSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/mixer_scarlett_gen2.c

@@ -1304,6 +1304,8 @@ static int scarlett2_sw_hw_enum_ctl_put(struct snd_kcontrol *kctl,
 	/* Send SW/HW switch change to the device */
 	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_SW_HW_SWITCH,
 				       index, val);
+	if (err == 0)
+		err = 1;
 
 unlock:
 	mutex_unlock(&private->data_mutex);
@@ -1364,6 +1366,8 @@ static int scarlett2_level_enum_ctl_put(struct snd_kcontrol *kctl,
 	/* Send switch change to the device */
 	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_LEVEL_SWITCH,
 				       index, val);
+	if (err == 0)
+		err = 1;
 
 unlock:
 	mutex_unlock(&private->data_mutex);
@@ -1414,6 +1418,8 @@ static int scarlett2_pad_ctl_put(struct snd_kcontrol *kctl,
 	/* Send switch change to the device */
 	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_PAD_SWITCH,
 				       index, val);
+	if (err == 0)
+		err = 1;
 
 unlock:
 	mutex_unlock(&private->data_mutex);
@@ -1469,6 +1475,8 @@ static int scarlett2_dim_mute_ctl_put(struct snd_kcontrol *kctl,
 	/* Send switch change to the device */
 	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_DIM_MUTE,
 				       index, val);
+	if (err == 0)
+		err = 1;
 
 unlock:
 	mutex_unlock(&private->data_mutex);