dma: sh: use an integer slave ID to improve API compatibility

Initially struct shdma_slave has been introduced with the only member - an
unsigned slave ID - to describe common properties of DMA slaves in an
extensible way. However, experience shows, that a slave ID is indeed the
only parameter, needed to identify DMA slaves. This is also, what is used
by the core dmaengine API in struct dma_slave_config. We switch to using
the slave_id directly, instead of passing a pointer to struct shdma_slave
to improve compatibility with the core. We also make the slave_id signed
for easier error checking.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
diff --git a/include/linux/sh_dma.h b/include/linux/sh_dma.h
index a79f10a..4e83f3e 100644
--- a/include/linux/sh_dma.h
+++ b/include/linux/sh_dma.h
@@ -27,10 +27,10 @@
  * a certain peripheral
  */
 struct sh_dmae_slave_config {
-	unsigned int			slave_id;
-	dma_addr_t			addr;
-	u32				chcr;
-	char				mid_rid;
+	int		slave_id;
+	dma_addr_t	addr;
+	u32		chcr;
+	char		mid_rid;
 };
 
 struct sh_dmae_channel {