ASoC: omap-mcpdm: Set 24msbits constraint

McPDM internal FIFO is 24 bit wide. From the 32 bit sample
8 bit is discarded. Let application know about this
via msbits constraint.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/omap/omap-mcpdm.c b/sound/soc/omap/omap-mcpdm.c
index 0e25df4..3970556 100644
--- a/sound/soc/omap/omap-mcpdm.c
+++ b/sound/soc/omap/omap-mcpdm.c
@@ -419,12 +419,14 @@
 		.channels_max = 5,
 		.rates = OMAP_MCPDM_RATES,
 		.formats = OMAP_MCPDM_FORMATS,
+		.sig_bits = 24,
 	},
 	.capture = {
 		.channels_min = 1,
 		.channels_max = 3,
 		.rates = OMAP_MCPDM_RATES,
 		.formats = OMAP_MCPDM_FORMATS,
+		.sig_bits = 24,
 	},
 	.ops = &omap_mcpdm_dai_ops,
 };