ASoC: omap: sdma-pcm: Fix modpost warning

WARNING: modpost: missing MODULE_LICENSE() in sound/soc/omap/snd-soc-sdma.o
see include/linux/module.h for more information
WARNING: modpost: missing MODULE_LICENSE() in sound/soc/omap/snd-soc-sdma.o
see include/linux/module.h for more information

Add the missing MODULE_LICENSE.

This patch also going to solve:
snd_soc_sdma: Unknown symbol devm_kmalloc (err 0)
snd_soc_sdma: Unknown symbol omap_dma_filter_fn (err 0)
snd_soc_sdma: Unknown symbol snd_dmaengine_pcm_prepare_slave_config (err 0)
snd_soc_sdma: Unknown symbol devm_snd_dmaengine_pcm_register (err 0)

Reported-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/omap/sdma-pcm.c

@@ -4,6 +4,7 @@
  *  Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
  */
 
+#include <linux/module.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
@@ -66,3 +67,7 @@ int sdma_pcm_platform_register(struct device *dev,
 	return devm_snd_dmaengine_pcm_register(dev, config, flags);
 }
 EXPORT_SYMBOL_GPL(sdma_pcm_platform_register);
+
+MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
+MODULE_DESCRIPTION("sDMA PCM ASoC platform driver");
+MODULE_LICENSE("GPL v2");