ALSA: mts64: Check card index validity at probe

Although mts64 driver has a check of the given devptr->id value, it
doesn't check for a negative id, which is often given as "none" or
such value when bound via sysfs.  This may lead to OOB access for
index[] and other parameters.

Add a sanity check for the card index and warn/correct it if it's a
value out of the range.

Cc: stable@vger.kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20260806153227.1460166-6-tiwai@suse.de

sound/drivers/mts64.c

@@ -900,6 +900,12 @@ static int snd_mts64_probe(struct platform_device *pdev)
 	p = platform_get_drvdata(pdev);
 	platform_set_drvdata(pdev, NULL);
 
+	if (dev < 0) {
+		dev_warn(&pdev->dev,
+			 "Invalid card index %d, using default 0\n", dev);
+		dev = 0;
+	}
+
 	if (dev >= SNDRV_CARDS)
 		return -ENODEV;
 	if (!enable[dev])