ipvlan: Fix text that talks about ip util support

ipvlan was added into 3.19 release and iproute2 added support
for the same in iproute2-3.19 package.
Signed-off-by: NMahesh Bandewar <maheshb@google.com>
CC: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/Kconfig

@@ -157,7 +157,7 @@ config IPVLAN
       making it transparent to the connected L2 switch.
 
       Ipvlan devices can be added using the "ip" command from the
-      iproute2 package starting with the iproute2-X.Y.ZZ release:
+      iproute2 package starting with the iproute2-3.19 release:
 
       "ip link add link <main-dev> [ NAME ] type ipvlan"