mptcp: add ADD_ADDR related mibs

This patch added two mibs for ADD_ADDR, MPTCP_MIB_ADDADDR for receiving
of the ADD_ADDR suboption with echo-flag=0, and MPTCP_MIB_ECHOADD for
receiving the ADD_ADDR suboption with echo-flag=1.

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/mptcp/mib.c b/net/mptcp/mib.c
index 056986c..a33bf71 100644
--- a/net/mptcp/mib.c
+++ b/net/mptcp/mib.c
@@ -27,6 +27,8 @@ static const struct snmp_mib mptcp_snmp_list[] = {
 	SNMP_MIB_ITEM("OFOMerge", MPTCP_MIB_OFOMERGE),
 	SNMP_MIB_ITEM("NoDSSInWindow", MPTCP_MIB_NODSSWINDOW),
 	SNMP_MIB_ITEM("DuplicateData", MPTCP_MIB_DUPDATA),
+	SNMP_MIB_ITEM("AddAddr", MPTCP_MIB_ADDADDR),
+	SNMP_MIB_ITEM("EchoAdd", MPTCP_MIB_ECHOADD),
 	SNMP_MIB_SENTINEL
 };