[BRIDGE]: limited ethtool support

Add limited ethtool support to bridge to allow disabling
features.

Note: if underlying device does not support a feature (like checksum
offload), then the bridge device won't inherit it.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 7ad53c2..db7b26b 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -93,6 +93,7 @@
 	spinlock_t			hash_lock;
 	struct hlist_head		hash[BR_HASH_SIZE];
 	struct list_head		age_list;
+	unsigned long			feature_mask;
 
 	/* STP */
 	bridge_id			designated_root;