ASoC: davinci-mcasp: Symmetric sample bits for IIS mode

In IIS mode the tx and rx configuration is symmetric, the BCLK and FSYNC is
shared.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/davinci/davinci-mcasp.c b/sound/soc/davinci/davinci-mcasp.c
index 57f606e..80c54ed 100644
--- a/sound/soc/davinci/davinci-mcasp.c
+++ b/sound/soc/davinci/davinci-mcasp.c
@@ -961,6 +961,7 @@
 		},
 		.ops 		= &davinci_mcasp_dai_ops,
 
+		.symmetric_samplebits	= 1,
 	},
 	{
 		.name		= "davinci-mcasp.1",