ALSA: scarlett2: Fix yet more -Wformat-truncation warnings

The recent code change introduced a few false-positive compile
warnings with -Wformat-trucation again.  Suppress them by replacing
snprintf() with scnprintf().

Fixes: 0a995e38 ("ALSA: scarlett2: Add support for software-controllable input gain")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202401062344.AzZCYlpa-lkp@intel.com/
Link: https://lore.kernel.org/r/20240112171000.31855-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/mixer_scarlett2.c

@@ -5361,7 +5361,7 @@ static int scarlett2_add_line_out_ctls(struct usb_mixer_interface *mixer)
 			if (private->vol_sw_hw_switch[index])
 				scarlett2_vol_ctl_set_writable(mixer, i, 0);
 
-			snprintf(s, sizeof(s),
+			scnprintf(s, sizeof(s),
 				  "Line Out %02d Volume Control Playback Enum",
 				  i + 1);
 			err = scarlett2_add_new_ctl(mixer,
@@ -5406,7 +5406,7 @@ static int scarlett2_add_line_in_ctls(struct usb_mixer_interface *mixer)
 
 	/* Add input level (line/inst) controls */
 	for (i = 0; i < info->level_input_count; i++) {
-		snprintf(s, sizeof(s), fmt, i + 1 + info->level_input_first,
+		scnprintf(s, sizeof(s), fmt, i + 1 + info->level_input_first,
 			  "Level", "Enum");
 		err = scarlett2_add_new_ctl(mixer, &scarlett2_level_enum_ctl,
 					    i, 1, s, &private->level_ctls[i]);
@@ -5416,7 +5416,7 @@ static int scarlett2_add_line_in_ctls(struct usb_mixer_interface *mixer)
 
 	/* Add input pad controls */
 	for (i = 0; i < info->pad_input_count; i++) {
-		snprintf(s, sizeof(s), fmt, i + 1, "Pad", "Switch");
+		scnprintf(s, sizeof(s), fmt, i + 1, "Pad", "Switch");
 		err = scarlett2_add_new_ctl(mixer, &scarlett2_pad_ctl,
 					    i, 1, s, &private->pad_ctls[i]);
 		if (err < 0)
@@ -5425,7 +5425,7 @@ static int scarlett2_add_line_in_ctls(struct usb_mixer_interface *mixer)
 
 	/* Add input air controls */
 	for (i = 0; i < info->air_input_count; i++) {
-		snprintf(s, sizeof(s), fmt, i + 1 + info->air_input_first,
+		scnprintf(s, sizeof(s), fmt, i + 1 + info->air_input_first,
 			  "Air", info->air_option ? "Enum" : "Switch");
 		err = scarlett2_add_new_ctl(
 			mixer, &scarlett2_air_ctl[info->air_option],
@@ -5481,7 +5481,7 @@ static int scarlett2_add_line_in_ctls(struct usb_mixer_interface *mixer)
 
 		for (i = 0; i < info->gain_input_count; i++) {
 			if (i % 2) {
-				snprintf(s, sizeof(s),
+				scnprintf(s, sizeof(s),
 					  "Line In %d-%d Link Capture Switch",
 					  i, i + 1);
 				err = scarlett2_add_new_ctl(
@@ -5492,7 +5492,7 @@ static int scarlett2_add_line_in_ctls(struct usb_mixer_interface *mixer)
 					return err;
 			}
 
-			snprintf(s, sizeof(s), fmt, i + 1,
+			scnprintf(s, sizeof(s), fmt, i + 1,
 				  "Gain", "Volume");
 			err = scarlett2_add_new_ctl(
 				mixer, &scarlett2_input_gain_ctl,
@@ -5500,7 +5500,7 @@ static int scarlett2_add_line_in_ctls(struct usb_mixer_interface *mixer)
 			if (err < 0)
 				return err;
 
-			snprintf(s, sizeof(s), fmt, i + 1,
+			scnprintf(s, sizeof(s), fmt, i + 1,
 				  "Autogain", "Switch");
 			err = scarlett2_add_new_ctl(
 				mixer, &scarlett2_autogain_switch_ctl,
@@ -5508,13 +5508,13 @@ static int scarlett2_add_line_in_ctls(struct usb_mixer_interface *mixer)
 			if (err < 0)
 				return err;
 
-			snprintf(s, sizeof(s), fmt, i + 1,
+			scnprintf(s, sizeof(s), fmt, i + 1,
 				  "Autogain Status", "Enum");
 			err = scarlett2_add_new_ctl(
 				mixer, &scarlett2_autogain_status_ctl,
 				i, 1, s, &private->autogain_status_ctls[i]);
 
-			snprintf(s, sizeof(s), fmt, i + 1,
+			scnprintf(s, sizeof(s), fmt, i + 1,
 				  "Safe", "Switch");
 			err = scarlett2_add_new_ctl(
 				mixer, &scarlett2_safe_ctl,
@@ -5902,7 +5902,7 @@ static int scarlett2_add_direct_monitor_ctls(struct usb_mixer_interface *mixer)
 			for (k = 0; k < private->num_mix_in; k++, index++) {
 				char name[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
 
-				snprintf(name, sizeof(name), format,
+				scnprintf(name, sizeof(name), format,
 					  mix_type, 'A' + j, k + 1);
 
 				err = scarlett2_add_new_ctl(