ASoC: Staticise nuc900_dma_getposition()

It is not used outside this driver so no need to make the symbol global.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/nuc900/nuc900-pcm.c

@@ -227,7 +227,7 @@ static int nuc900_dma_trigger(struct snd_pcm_substream *substream, int cmd)
 	return ret;
 }
 
-int nuc900_dma_getposition(struct snd_pcm_substream *substream,
+static int nuc900_dma_getposition(struct snd_pcm_substream *substream,
 					dma_addr_t *src, dma_addr_t *dst)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;