ipv6: fix checkpatch errors of "foo*" and "foo * bar"

ERROR: "(foo*)" should be "(foo *)"
ERROR: "foo * bar" should be "foo *bar"

Suggested-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Acked-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>