ASoC: dwc: Unmask I2S interrupts only for enabled channels

There is no need to unmask all interrupts at I2S start. This
can cause performance issues in slower platforms.

Unmask only the interrupts for the used channels.

Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/dwc/designware_i2s.c b/sound/soc/dwc/designware_i2s.c
index bff258d..3effcd1 100644
--- a/sound/soc/dwc/designware_i2s.c
+++ b/sound/soc/dwc/designware_i2s.c
@@ -147,17 +147,18 @@
 static void i2s_start(struct dw_i2s_dev *dev,
 		      struct snd_pcm_substream *substream)
 {
+	struct i2s_clk_config_data *config = &dev->config;
 	u32 i, irq;
 	i2s_write_reg(dev->i2s_base, IER, 1);
 
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
-		for (i = 0; i < 4; i++) {
+		for (i = 0; i < (config->chan_nr / 2); i++) {
 			irq = i2s_read_reg(dev->i2s_base, IMR(i));
 			i2s_write_reg(dev->i2s_base, IMR(i), irq & ~0x30);
 		}
 		i2s_write_reg(dev->i2s_base, ITER, 1);
 	} else {
-		for (i = 0; i < 4; i++) {
+		for (i = 0; i < (config->chan_nr / 2); i++) {
 			irq = i2s_read_reg(dev->i2s_base, IMR(i));
 			i2s_write_reg(dev->i2s_base, IMR(i), irq & ~0x03);
 		}