Phonet: proc interface for port range

Phonet endpoints are bound to individual ports.
This provides a /proc/sys/net/phonet (or sysctl) interface for
selecting the range of automatically allocated ports (much like the
ip_local_port_range with IPv4).

Signed-off-by: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/phonet/Makefile b/net/phonet/Makefile
index d218abc..ae9c3ed 100644
--- a/net/phonet/Makefile
+++ b/net/phonet/Makefile
@@ -5,4 +5,5 @@
 	pn_netlink.o \
 	socket.o \
 	datagram.o \
+	sysctl.o \
 	af_phonet.o