packet : remove init_net restriction

The af_packet protocol is used by Perl to do ioctls as reported by
Stephane Riviere:

"Net::RawIP relies on SIOCGIFADDR et SIOCGIFHWADDR to get the IP and MAC
addresses of the network interface."

But in a new network namespace these ioctl fail because it is disabled for
a namespace different from the init_net_ns.

These two lines should not be there as af_inet and af_packet are
namespace aware since a long time now. I suppose we forget to remove these
lines because we sent the af_packet first, before af_inet was supported.
Signed-off-by: NDaniel Lezcano <daniel.lezcano@free.fr>
Reported-by: NStephane Riviere <stephane.riviere@regis-dgac.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/packet/af_packet.c

@@ -2169,8 +2169,6 @@ static int packet_ioctl(struct socket *sock, unsigned int cmd,
 	case SIOCGIFDSTADDR:
 	case SIOCSIFDSTADDR:
 	case SIOCSIFFLAGS:
-		if (!net_eq(sock_net(sk), &init_net))
-			return -ENOIOCTLCMD;
 		return inet_dgram_ops.ioctl(sock, cmd, arg);
 #endif