ASoC: ssm2518: Fix trivial typo in checking tx_mask and rx_mask values

Otherwise, ssm2518_set_tdm_slot() always returns error if slots != 0.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/codecs/ssm2518.c

@@ -539,7 +539,7 @@ static int ssm2518_set_tdm_slot(struct snd_soc_dai *dai, unsigned int tx_mask,
 			SSM2518_REG_SAI_CTRL1, SSM2518_SAI_CTRL1_SAI_MASK,
 			SSM2518_SAI_CTRL1_SAI_I2S);
 
-	if (tx_mask == 0 || tx_mask != 0)
+	if (tx_mask == 0 || rx_mask != 0)
 		return -EINVAL;
 
 	if (slots == 1) {