netvsc: keep track of some non-fatal overload conditions

Add ethtool statistics for case where send chimmeny buffer is
exhausted and driver has to fall back to doing scatter/gather
send. Also, add statistic for case where ring buffer is full and
receive completions are delayed.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 3032637..9198dd1 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -680,6 +680,8 @@ struct netvsc_ethtool_stats {
 	unsigned long tx_no_space;
 	unsigned long tx_too_big;
 	unsigned long tx_busy;
+	unsigned long tx_send_full;
+	unsigned long rx_comp_busy;
 };
 
 struct netvsc_vf_pcpu_stats {