net: ETHOC should depend on HAS_DMA

When building for Sun 3:

drivers/net/ethoc.c:1091: undefined reference to `dma_free_coherent'
drivers/built-in.o: In function `ethoc_probe':
drivers/net/ethoc.c:965: undefined reference to `dma_alloc_coherent'
drivers/net/ethoc.c:1063: undefined reference to `dma_free_coherent'
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/Kconfig

@@ -975,7 +975,7 @@ config ENC28J60_WRITEVERIFY
 
 config ETHOC
 	tristate "OpenCores 10/100 Mbps Ethernet MAC support"
-	depends on NET_ETHERNET && HAS_IOMEM
+	depends on NET_ETHERNET && HAS_IOMEM && HAS_DMA
 	select MII
 	select PHYLIB
 	select CRC32