ASoC/mpc5200: Track DMA position by period number instead of bytes

All DMA blocks are lined up to period boundaries, but the DMA
handling code tracks bytes instead.  This patch reworks the code
to track the period index into the DMA buffer instead of the
physical address pointer.  Doing so makes the code simpler and
easier to understand.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/fsl/mpc5200_dma.h b/sound/soc/fsl/mpc5200_dma.h
index 8d396bb..529f7a0 100644
--- a/sound/soc/fsl/mpc5200_dma.h
+++ b/sound/soc/fsl/mpc5200_dma.h
@@ -13,7 +13,6 @@
  * @psc_dma:		pointer back to parent psc_dma data structure
  * @bcom_task:		bestcomm task structure
  * @irq:		irq number for bestcomm task
- * @period_start:	physical address of start of DMA region
  * @period_end:		physical address of end of DMA region
  * @period_next_pt:	physical address of next DMA buffer to enqueue
  * @period_bytes:	size of DMA period in bytes
@@ -27,12 +26,9 @@
 	struct bcom_task *bcom_task;
 	int irq;
 	struct snd_pcm_substream *stream;
-	dma_addr_t period_start;
-	dma_addr_t period_end;
-	dma_addr_t period_next_pt;
-	dma_addr_t period_current_pt;
+	int period_next;
+	int period_current;
 	int period_bytes;
-	int period_size;
 };
 
 /**