ip6_gre: correct the function name in ip6gre_tnl_addr_conflict() comment

The function name is wrong in ip6gre_tnl_addr_conflict() comment, which
use ip6_tnl_addr_conflict instead of ip6gre_tnl_addr_conflict.
Signed-off-by: NSun Lianwen <sunlw.fnst@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/ip6_gre.c

@@ -807,7 +807,7 @@ static inline int ip6gre_xmit_ipv6(struct sk_buff *skb, struct net_device *dev)
 }
 
 /**
- * ip6_tnl_addr_conflict - compare packet addresses to tunnel's own
+ * ip6gre_tnl_addr_conflict - compare packet addresses to tunnel's own
  *   @t: the outgoing tunnel device
  *   @hdr: IPv6 header from the incoming packet
  *