sh_eth: add sh_eth_cpu_data::soft_reset() method

sh_eth_reset() performs a software reset which is implemented in a
completely different way for the GEther-like controllers vs the other
controllers due to a different layout of EDMR (and other factors) --
it therefore makes sense to convert this function to a mandatory
sh_eth_cpu_data::soft_reset() method and thus get rid of the runtime
controller type check via sh_eth_is_{gether|rz_fast_ether}().

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/renesas/sh_eth.h

@@ -469,6 +469,9 @@ struct sh_eth_rxdesc {
 
 /* This structure is used by each CPU dependency handling. */
 struct sh_eth_cpu_data {
+	/* mandatory functions */
+	int (*soft_reset)(struct net_device *ndev);
+
 	/* optional functions */
 	void (*chip_reset)(struct net_device *ndev);
 	void (*set_duplex)(struct net_device *ndev);