ASoC: Intel: sst: remove redundant variable dma_dev_name

The pointer dma_dev_name is assigned but never read, it is redundant
and can therefore be removed.

Cleans up clang warning:
sound/soc/intel/common/sst-firmware.c:288:3: warning: Value stored to
'dma_dev_name' is never read
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/common/sst-firmware.c

@@ -274,7 +274,6 @@ int sst_dma_new(struct sst_dsp *sst)
 	struct sst_pdata *sst_pdata = sst->pdata;
 	struct sst_dma *dma;
 	struct resource mem;
-	const char *dma_dev_name;
 	int ret = 0;
 
 	if (sst->pdata->resindex_dma_base == -1)
@@ -285,7 +284,6 @@ int sst_dma_new(struct sst_dsp *sst)
 	* is attached to the ADSP IP. */
 	switch (sst->pdata->dma_engine) {
 	case SST_DMA_TYPE_DW:
-		dma_dev_name = "dw_dmac";
 		break;
 	default:
 		dev_err(sst->dev, "error: invalid DMA engine %d\n",