[PATCH] sky2 needs dma_mapping.h

On alpha:

drivers/net/sky2.c: In function `sky2_probe':
drivers/net/sky2.c:2819: error: `DMA_64BIT_MASK' undeclared (first use in this function)
drivers/net/sky2.c:2819: error: (Each undeclared identifier is reported only once
drivers/net/sky2.c:2819: error: for each function it appears in.)
drivers/net/sky2.c:2825: error: `DMA_32BIT_MASK' undeclared (first use in this function)

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>