sh_eth: SH_ETH should depend on HAS_DMA

If NO_DMA=y:

drivers/built-in.o: In function `sh_eth_free_dma_buffer':
drivers/net/ethernet/renesas/sh_eth.c:1103: undefined reference to `dma_free_coherent'
drivers/net/ethernet/renesas/sh_eth.c:1110: undefined reference to `dma_free_coherent'
drivers/built-in.o: In function `sh_eth_ring_init':
drivers/net/ethernet/renesas/sh_eth.c:1065: undefined reference to `dma_alloc_coherent'
drivers/net/ethernet/renesas/sh_eth.c:1086: undefined reference to `dma_free_coherent'
drivers/built-in.o: In function `sh_eth_ring_format':
drivers/net/ethernet/renesas/sh_eth.c:988: undefined reference to `dma_map_single'
drivers/built-in.o: In function `sh_eth_txfree':
drivers/net/ethernet/renesas/sh_eth.c:1220: undefined reference to `dma_unmap_single'
drivers/built-in.o: In function `sh_eth_rx':
drivers/net/ethernet/renesas/sh_eth.c:1323: undefined reference to `dma_map_single'
drivers/built-in.o: In function `sh_eth_start_xmit':
drivers/net/ethernet/renesas/sh_eth.c:1954: undefined reference to `dma_map_single'

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David S. Miller <davem@davemloft.net>