ALSA: atmel/ac97c: correct the unexpected behavior when using uninitial value for reset pin

When pdata->reset_pin is passed with a negative value (means gpio
is invalid), then chip->reset_pin will not be assigned to a vaule,
it will use default value 0. This will cause unexpected behavior.

So, add this patch to correct.

Signed-off-by: Bo Shen <voice.shen@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/atmel/ac97c.c b/sound/atmel/ac97c.c
index 115313e..f5ded64 100644
--- a/sound/atmel/ac97c.c
+++ b/sound/atmel/ac97c.c
@@ -991,6 +991,8 @@
 			gpio_direction_output(pdata->reset_pin, 1);
 			chip->reset_pin = pdata->reset_pin;
 		}
+	} else {
+		chip->reset_pin = -EINVAL;
 	}
 
 	snd_card_set_dev(card, &pdev->dev);