net: ks8842 depends on DMA_ENGINE

ks8842 uses dma channel functions, so it should depend on DMA_ENGINE.

ERROR: "__dma_request_channel" [drivers/net/ks8842.ko] undefined!
ERROR: "dma_release_channel" [drivers/net/ks8842.ko] undefined!

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>