dma-mapping: replace all DMA_48BIT_MASK macro with DMA_BIT_MASK(48)

Replace all DMA_48BIT_MASK macro with DMA_BIT_MASK(48)

Signed-off-by: Yang Hongyang<yanghy@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/net/dl2k.c

@@ -714,7 +714,7 @@ rio_interrupt (int irq, void *dev_instance)
 
 static inline dma_addr_t desc_to_dma(struct netdev_desc *desc)
 {
-	return le64_to_cpu(desc->fraginfo) & DMA_48BIT_MASK;
+	return le64_to_cpu(desc->fraginfo) & DMA_BIT_MASK(48);
 }
 
 static void