sfc: Enable RX checksum offload for packets not handled by GRO

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c
index a7dfe36c..b915e09 100644
--- a/drivers/net/ethernet/sfc/rx.c
+++ b/drivers/net/ethernet/sfc/rx.c
@@ -598,6 +598,8 @@
 
 	/* Set the SKB flags */
 	skb_checksum_none_assert(skb);
+	if (likely(rx_buf->flags & EFX_RX_PKT_CSUMMED))
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
 
 	if (channel->type->receive_skb)
 		if (channel->type->receive_skb(channel, skb))