ASoC: edma-pcm: Include edma-pcm.h

edma_pcm_platform_register() is declared in edma-pcm.h and defined in
edma-pcm.c. To make sure that the function signature matches for both
edma-pcm.c should include edma-pcm.h

Fixes the following sparse warning:
	sound/soc/davinci/edma-pcm.c:48:5: warning: symbol
	 'edma_pcm_platform_register' was not declared. Should it be static?

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/davinci/edma-pcm.c

@@ -25,6 +25,8 @@
 #include <sound/dmaengine_pcm.h>
 #include <linux/edma.h>
 
+#include "edma-pcm.h"
+
 static const struct snd_pcm_hardware edma_pcm_hardware = {
 	.info			= SNDRV_PCM_INFO_MMAP |
 				  SNDRV_PCM_INFO_MMAP_VALID |