[PATCH] dl2k needs dma-mapping.h

On alpha:

drivers/net/dl2k.c: In function `rio_free_tx':
drivers/net/dl2k.c:768: error: `DMA_48BIT_MASK' undeclared (first use in this function)
drivers/net/dl2k.c:768: error: (Each undeclared identifier is reported only once
drivers/net/dl2k.c:768: error: for each function it appears in.)
drivers/net/dl2k.c: In function `receive_packet':
drivers/net/dl2k.c:896: error: `DMA_48BIT_MASK' undeclared (first use in this function)
drivers/net/dl2k.c: In function `rio_close':
drivers/net/dl2k.c:1803: error: `DMA_48BIT_MASK' undeclared (first use in this function)

Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>