ip6_gre: only increase err_count for some certain type icmpv6 in ip6gre_err
The similar fix in patch 'ipip: only increase err_count for some
certain type icmp in ipip_err' is needed for ip6gre_err.
In Jianlin's case, udp netperf broke even when receiving a TooBig
icmpv6 packet.
Fixes: c12b395a4664 ("gre: Support GRE over IPv6") Reported-by: Jianlin Shi <jishi@redhat.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>