ASoC: pxa: Add .owner to struct snd_soc_card

Missed .owner of struct snd_soc_card will prevent the module from being
removed from underneath its users.

Reported-by: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/pxa/z2.c

@@ -202,6 +202,7 @@ static struct snd_soc_dai_link z2_dai = {
 /* z2 audio machine driver */
 static struct snd_soc_card snd_soc_z2 = {
 	.name		= "Z2",
+	.owner		= THIS_MODULE,
 	.dai_link	= &z2_dai,
 	.num_links	= 1,
 };