[SOCKET]: Export __sock_recv_timestamp

Kernel: arch/x86_64/boot/bzImage is ready  (#2)
  MODPOST 1816 modules
WARNING: "__sock_recv_timestamp" [net/sctp/sctp.ko] undefined!
WARNING: "__sock_recv_timestamp" [net/packet/af_packet.ko] undefined!
WARNING: "__sock_recv_timestamp" [net/key/af_key.ko] undefined!
WARNING: "__sock_recv_timestamp" [net/ipv6/ipv6.ko] undefined!
WARNING: "__sock_recv_timestamp" [net/atm/atm.ko] undefined!
make[2]: *** [__modpost] Error 1
make[1]: *** [modules] Error 2
make: *** [_all] Error 2
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/socket.c

@@ -614,6 +614,8 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
 	}
 }
 
+EXPORT_SYMBOL_GPL(__sock_recv_timestamp);
+
 static inline int __sock_recvmsg(struct kiocb *iocb, struct socket *sock,
 				 struct msghdr *msg, size_t size, int flags)
 {