smsc95xx: add wol magic packet support

This patch enables wake from system suspend on magic packet.

Patch updated to replace BUG_ON with WARN_ON_ONCE and return.

Signed-off-by: Steve Glendinning <steve.glendinning@shawell.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/usb/smsc95xx.h b/drivers/net/usb/smsc95xx.h
index 89ad925..2ff9815 100644
--- a/drivers/net/usb/smsc95xx.h
+++ b/drivers/net/usb/smsc95xx.h
@@ -205,6 +205,11 @@
 #define WUFF				(0x128)
 
 #define WUCSR				(0x12C)
+#define WUCSR_GUE_			(0x00000200)
+#define WUCSR_WUFR_			(0x00000040)
+#define WUCSR_MPR_			(0x00000020)
+#define WUCSR_WAKE_EN_			(0x00000004)
+#define WUCSR_MPEN_			(0x00000002)
 
 #define COE_CR				(0x130)
 #define Tx_COE_EN_			(0x00010000)