ASoC: fsl_ssi: Fix platform_get_irq() error handling

We should check whether platform_get_irq() returns a negative number and
propagate the error in this case.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/fsl_ssi.c

@@ -1357,7 +1357,7 @@ static int fsl_ssi_probe(struct platform_device *pdev)
 	}
 
 	ssi_private->irq = platform_get_irq(pdev, 0);
-	if (!ssi_private->irq) {
+	if (ssi_private->irq < 0) {
 		dev_err(&pdev->dev, "no irq for node %s\n", pdev->name);
 		return ssi_private->irq;
 	}