ravb: factor out register bit twiddling code

The  driver has often repeated pattern of reading a register,  AND'ing and/or
OR'ing some bits  and writing  the  value back. Factor the pattern out into
ravb_modify() -- this saves 260 bytes of code with ARM gcc 4.7.3.

While at it, update Cogent Embedded's copyrights.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h
index 9fbe92a..b2160d1 100644
--- a/drivers/net/ethernet/renesas/ravb.h
+++ b/drivers/net/ethernet/renesas/ravb.h
@@ -2,7 +2,7 @@
  *
  * Copyright (C) 2014-2015 Renesas Electronics Corporation
  * Copyright (C) 2015 Renesas Solutions Corp.
- * Copyright (C) 2015 Cogent Embedded, Inc. <source@cogentembedded.com>
+ * Copyright (C) 2015-2016 Cogent Embedded, Inc. <source@cogentembedded.com>
  *
  * Based on the SuperH Ethernet driver
  *
@@ -837,6 +837,8 @@
 	iowrite32(data, priv->addr + reg);
 }
 
+void ravb_modify(struct net_device *ndev, enum ravb_reg reg, u32 clear,
+		 u32 set);
 int ravb_wait(struct net_device *ndev, enum ravb_reg reg, u32 mask, u32 value);
 
 irqreturn_t ravb_ptp_interrupt(struct net_device *ndev);