net: Add GARP applicant-only participant

Add an implementation of the GARP (Generic Attribute Registration Protocol)
applicant-only participant. This will be used by the following patch to
add GVRP support to the VLAN code.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/802/Kconfig b/net/802/Kconfig
index 01cb094..be33d27 100644
--- a/net/802/Kconfig
+++ b/net/802/Kconfig
@@ -1,3 +1,7 @@
 config STP
 	tristate
 	select LLC
+
+config GARP
+	tristate
+	select STP