net: Convert ethtool {get_stats, self_test}_count() ops to get_sset_count()

These string query operations were supposed to be replaced by the
generic get_sset_count() starting in 2007.  Convert the remaining
implementations.

Also remove calls to these operations to initialise drvinfo->n_stats.
The ethtool core code already does that.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Acked-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/niu.c b/drivers/net/niu.c
index f9364d0..1d1e657 100644
--- a/drivers/net/niu.c
+++ b/drivers/net/niu.c
@@ -7855,10 +7855,13 @@
 	}
 }
 
-static int niu_get_stats_count(struct net_device *dev)
+static int niu_get_sset_count(struct net_device *dev, int stringset)
 {
 	struct niu *np = netdev_priv(dev);
 
+	if (stringset != ETH_SS_STATS)
+		return -EINVAL;
+
 	return ((np->flags & NIU_FLAGS_XMAC ?
 		 NUM_XMAC_STAT_KEYS :
 		 NUM_BMAC_STAT_KEYS) +
@@ -7978,7 +7981,7 @@
 	.get_settings		= niu_get_settings,
 	.set_settings		= niu_set_settings,
 	.get_strings		= niu_get_strings,
-	.get_stats_count	= niu_get_stats_count,
+	.get_sset_count		= niu_get_sset_count,
 	.get_ethtool_stats	= niu_get_ethtool_stats,
 	.phys_id		= niu_phys_id,
 	.get_rxnfc		= niu_get_nfc,