ASoC: omap-hdmi-audio: add NULL test

Add NULL test on call to devm_kzalloc.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression x;
identifier fld;
@@

* x = devm_kzalloc(...);
  ... when != x == NULL
  x->fld
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/omap/omap-hdmi-audio.c

@@ -368,6 +368,8 @@ static int omap_hdmi_audio_probe(struct platform_device *pdev)
 	card->owner = THIS_MODULE;
 	card->dai_link =
 		devm_kzalloc(dev, sizeof(*(card->dai_link)), GFP_KERNEL);
+	if (!card->dai_link)
+		return -ENOMEM;
 	card->dai_link->name = card->name;
 	card->dai_link->stream_name = card->name;
 	card->dai_link->cpu_dai_name = dev_name(ad->dssdev);