ena: Update driver to use ethtool_sprintf

Replace instances of snprintf or memcpy with a pointer update with
ethtool_sprintf.
Acked-by: NArthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: NAlexander Duyck <alexanderduyck@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/amazon/ena/ena_ethtool.c

@@ -251,10 +251,10 @@ static void ena_queue_strings(struct ena_adapter *adapter, u8 **data)
 		for (j = 0; j < ENA_STATS_ARRAY_TX; j++) {
 			ena_stats = &ena_stats_tx_strings[j];
 
-			snprintf(*data, ETH_GSTRING_LEN,
-				 "queue_%u_%s_%s", i,
-				 is_xdp ? "xdp_tx" : "tx", ena_stats->name);
-			(*data) += ETH_GSTRING_LEN;
+			ethtool_sprintf(data,
+					"queue_%u_%s_%s", i,
+					is_xdp ? "xdp_tx" : "tx",
+					ena_stats->name);
 		}
 
 		if (!is_xdp) {
@@ -264,9 +264,9 @@ static void ena_queue_strings(struct ena_adapter *adapter, u8 **data)
 			for (j = 0; j < ENA_STATS_ARRAY_RX; j++) {
 				ena_stats = &ena_stats_rx_strings[j];
 
-				snprintf(*data, ETH_GSTRING_LEN,
-					 "queue_%u_rx_%s", i, ena_stats->name);
-				(*data) += ETH_GSTRING_LEN;
+				ethtool_sprintf(data,
+						"queue_%u_rx_%s", i,
+						ena_stats->name);
 			}
 		}
 	}
@@ -280,9 +280,8 @@ static void ena_com_dev_strings(u8 **data)
 	for (i = 0; i < ENA_STATS_ARRAY_ENA_COM; i++) {
 		ena_stats = &ena_stats_ena_com_strings[i];
 
-		snprintf(*data, ETH_GSTRING_LEN,
-			 "ena_admin_q_%s", ena_stats->name);
-		(*data) += ETH_GSTRING_LEN;
+		ethtool_sprintf(data,
+				"ena_admin_q_%s", ena_stats->name);
 	}
 }
 
@@ -295,15 +294,13 @@ static void ena_get_strings(struct ena_adapter *adapter,
 
 	for (i = 0; i < ENA_STATS_ARRAY_GLOBAL; i++) {
 		ena_stats = &ena_stats_global_strings[i];
-		memcpy(data, ena_stats->name, ETH_GSTRING_LEN);
-		data += ETH_GSTRING_LEN;
+		ethtool_sprintf(&data, ena_stats->name);
 	}
 
 	if (eni_stats_needed) {
 		for (i = 0; i < ENA_STATS_ARRAY_ENI(adapter); i++) {
 			ena_stats = &ena_stats_eni_strings[i];
-			memcpy(data, ena_stats->name, ETH_GSTRING_LEN);
-			data += ETH_GSTRING_LEN;
+			ethtool_sprintf(&data, ena_stats->name);
 		}
 	}