qlcnic: additional driver statistics

Added additional driver statistics to track errors in rcv/tx path.

Signed-off-by: Amit Kumar Salecha <amit.salecha@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/qlcnic/qlcnic.h b/drivers/net/qlcnic/qlcnic.h
index 28c148c..6c1da71 100644
--- a/drivers/net/qlcnic/qlcnic.h
+++ b/drivers/net/qlcnic/qlcnic.h
@@ -428,6 +428,10 @@
 	u64  xmit_on;
 	u64  xmit_off;
 	u64  skb_alloc_failure;
+	u64  null_skb;
+	u64  null_rxbuf;
+	u64  rx_dma_map_error;
+	u64  tx_dma_map_error;
 };
 
 /*