ASoC: fsl_ssi: Change irq type to 'int'

Since commit 2ffa5310 ("ASoC: fsl_ssi: Fix module unbound") the irq
number is retrieved via platform_get_irq(), which may fail and return a negative
number, so adapt its type to 'int'.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/fsl_ssi.c

@@ -160,7 +160,7 @@ struct fsl_ssi_soc_data {
  */
 struct fsl_ssi_private {
 	struct regmap *regs;
-	unsigned int irq;
+	int irq;
 	struct snd_soc_dai_driver cpu_dai_drv;
 
 	unsigned int dai_fmt;