[BRIDGE]: use llc for receiving STP packets

Use LLC for the receive path of Spanning Tree Protocol packets.
This allows link local multicast packets to be received by
other protocols (if they care), and uses the existing LLC
code to get STP packets back into bridge code.

The bridge multicast address is also checked, so bridges using
other link local multicast addresses are ignored. This allows
for use of different multicast addresses to define separate STP
domains.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/Kconfig b/net/bridge/Kconfig
index db23d59..12265af 100644
--- a/net/bridge/Kconfig
+++ b/net/bridge/Kconfig
@@ -4,6 +4,7 @@
 
 config BRIDGE
 	tristate "802.1d Ethernet Bridging"
+	select LLC
 	---help---
 	  If you say Y here, then your Linux box will be able to act as an
 	  Ethernet bridge, which means that the different Ethernet segments it