powerpc: add dma_capable() to replace is_buffer_dma_capable()

dma_capable() eventually replaces is_buffer_dma_capable(), which tells
if a memory area is dma-capable or not. The problem of
is_buffer_dma_capable() is that it doesn't take a pointer to struct
device so it doesn't work for POWERPC.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Becky Bruce <beckyb@kernel.crashing.org>

arch/powerpc/include/asm/dma-mapping.h

@@ -424,6 +424,19 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 #endif
 }
 
+static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
+{
+	struct dma_mapping_ops *ops = get_dma_ops(dev);
+
+	if (ops->addr_needs_map && ops->addr_needs_map(dev, addr, size))
+		return 0;
+
+	if (!dev->dma_mask)
+		return 0;
+
+	return addr + size <= *dev->dma_mask;
+}
+
 #define dma_alloc_noncoherent(d, s, h, f) dma_alloc_coherent(d, s, h, f)
 #define dma_free_noncoherent(d, s, v, h) dma_free_coherent(d, s, v, h)
 #ifdef CONFIG_NOT_COHERENT_CACHE