Make DMA interface chip independent

The common DMA interface should not include chip dependent stuff.
Otherwise we cannot share DMA interface across chips.

BUG=None
TEST=make buildall
BRANCH=None

Change-Id: I9e0d0c0637520c613747110d6c65d3b800e01704
Signed-off-by: Vic Yang <victoryang@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/205066
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

chip/stm32/registers.h

@@ -1130,6 +1130,9 @@ struct stm32_dma_chan {
 /* Always use stm32_dma_chan_t so volatile keyword is included! */
 typedef volatile struct stm32_dma_chan stm32_dma_chan_t;
 
+/* Common code and header file must use this */
+typedef stm32_dma_chan_t dma_chan_t;
+
 /* Registers for the DMA controller */
 struct stm32_dma_regs {
 	uint32_t	isr;

include/dma.h

@@ -30,7 +30,7 @@ struct dma_option {
  * @param channel	Channel to read
  * @return pointer to DMA channel registers
  */
-stm32_dma_chan_t *dma_get_channel(enum dma_channel channel);
+dma_chan_t *dma_get_channel(enum dma_channel channel);
 
 /**
  * Prepare a DMA transfer to transmit data from memory to a peripheral
@@ -76,14 +76,14 @@ void dma_disable(enum dma_channel channel);
  * @return number of bytes completed on a channel, or 0 if this channel is
  *		not enabled
  */
-int dma_bytes_done(stm32_dma_chan_t *chan, int orig_count);
+int dma_bytes_done(dma_chan_t *chan, int orig_count);
 
 /**
  * Start a previously-prepared dma channel
  *
  * @param chan	Channel to start, from dma_get_channel()
  */
-void dma_go(stm32_dma_chan_t *chan);
+void dma_go(dma_chan_t *chan);
 
 #ifdef CONFIG_DMA_HELP
 /**