stmmac: move the dma out from the main

This patch moves the dma related functions (interrupt, start, stop etc.)
out from the main driver code. This will help to support new DMA
engines.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/stmmac/stmmac_ethtool.c b/drivers/net/stmmac/stmmac_ethtool.c
index 9c7ce1e..0abeff6 100644
--- a/drivers/net/stmmac/stmmac_ethtool.c
+++ b/drivers/net/stmmac/stmmac_ethtool.c
@@ -28,6 +28,7 @@
 #include <linux/phy.h>
 
 #include "stmmac.h"
+#include "dwmac_dma.h"
 
 #define REG_SPACE_SIZE	0x1054
 #define MAC100_ETHTOOL_NAME	"st_mac100"