sfc: Implement generic features interface

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/sfc/rx.c b/drivers/net/sfc/rx.c
index fb402c5..b7dc891 100644
--- a/drivers/net/sfc/rx.c
+++ b/drivers/net/sfc/rx.c
@@ -605,7 +605,7 @@
 		skb_record_rx_queue(skb, channel->channel);
 	}
 
-	if (unlikely(!efx->rx_checksum_enabled))
+	if (unlikely(!(efx->net_dev->features & NETIF_F_RXCSUM)))
 		checksummed = false;
 
 	if (likely(checksummed || rx_buf->is_page)) {