DMA-API: amba: get rid of separate dma_mask

AMBA Primecell devices always treat streaming and coherent DMA exactly
the same, so there's no point in having the masks separated.

Acked-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

include/linux/amba/bus.h

@@ -30,7 +30,6 @@ struct amba_device {
 	struct device		dev;
 	struct resource		res;
 	struct clk		*pclk;
-	u64			dma_mask;
 	unsigned int		periphid;
 	unsigned int		irq[AMBA_NR_IRQS];
 };
@@ -131,7 +130,6 @@ struct amba_device name##_device = {				\
 struct amba_device name##_device = {				\
 	.dev = __AMBA_DEV(busid, data, ~0ULL),			\
 	.res = DEFINE_RES_MEM(base, SZ_4K),			\
-	.dma_mask = ~0ULL,					\
 	.irq = irqs,						\
 	.periphid = id,						\
 }