net: ipv6: Set protocol to kernel for local routes

IPv6 stack does not set the protocol for local routes, so those routes show
up with proto "none":
    $ ip -6 ro ls table local
    local ::1 dev lo proto none metric 0  pref medium
    local 2100:3:: dev lo proto none metric 0  pref medium
    local 2100:3::4 dev lo proto none metric 0  pref medium
    local fe80:: dev lo proto none metric 0  pref medium
    ...

Set rt6i_protocol to RTPROT_KERNEL for consistency with IPv4. Now routes
show up with proto "kernel":
    $ ip -6 ro ls table local
    local ::1 dev lo proto kernel metric 0  pref medium
    local 2100:3:: dev lo proto kernel metric 0  pref medium
    local 2100:3::4 dev lo proto kernel metric 0  pref medium
    local fe80:: dev lo proto kernel metric 0  pref medium
    ...
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/route.c

@@ -2634,6 +2634,7 @@ struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev,
 	rt->dst.output = ip6_output;
 	rt->rt6i_idev = idev;
 
+	rt->rt6i_protocol = RTPROT_KERNEL;
 	rt->rt6i_flags = RTF_UP | RTF_NONEXTHOP;
 	if (anycast)
 		rt->rt6i_flags |= RTF_ANYCAST;