be2net: cleanup rx/tx rate calculations

Hi, Pls accept this patch to cleanup rx/tx rate calculations as follows:
- check for jiffies wraparound
- remove typecast of a denominator
- do rate calculation only in workqueue context periodically

Signed-off-by: Sathya Perla <sathyap@serverengines.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/benet/be.h b/drivers/net/benet/be.h
index f327be5..c49ddd0 100644
--- a/drivers/net/benet/be.h
+++ b/drivers/net/benet/be.h
@@ -100,9 +100,9 @@
 	u32 be_tx_wrbs;		/* number of tx WRBs used */
 	u32 be_tx_events;	/* number of tx completion events  */
 	u32 be_tx_compl;	/* number of tx completion entries processed */
-	u64 be_tx_jiffies;
-	ulong be_tx_bytes;
-	ulong be_tx_bytes_prev;
+	ulong be_tx_jiffies;
+	u64 be_tx_bytes;
+	u64 be_tx_bytes_prev;
 	u32 be_tx_rate;
 
 	u32 cache_barrier[16];
@@ -113,9 +113,9 @@
 	u32 be_rx_compl;	/* number of rx completion entries processed */
 	u32 be_lro_hgram_data[8];	/* histogram of LRO data packets */
 	u32 be_lro_hgram_ack[8];	/* histogram of LRO ACKs */
-	u64 be_rx_jiffies;
-	ulong be_rx_bytes;
-	ulong be_rx_bytes_prev;
+	ulong be_rx_jiffies;
+	u64 be_rx_bytes;
+	u64 be_rx_bytes_prev;
 	u32 be_rx_rate;
 	/* number of non ether type II frames dropped where
 	 * frame len > length field of Mac Hdr */