ipv6: fix IPV6_ADDRFORM operation logic

ipv6: fix IPV6_ADDRFORM operation logic

Socket option IPV6_ADDRFORM supports UDP/UDPLITE and TCP at present.
Previously the checking logic looks like:
if (sk->sk_protocol == IPPROTO_UDP || sk->sk_protocol == IPPROTO_UDPLITE)
	do_some_check;
else if (sk->sk_protocol != IPPROTO_TCP)
	break;

After commit 636babcef96a ("ipv6: restrict IPV6_ADDRFORM operation"), TCP
was blocked as the logic changed to:
if (sk->sk_protocol == IPPROTO_UDP || sk->sk_protocol == IPPROTO_UDPLITE)
	do_some_check;
else if (sk->sk_protocol == IPPROTO_TCP)
	do_some_check;
	break;
else
	break;

Then after commit 963166e0162a ("ipv6: fix restrict IPV6_ADDRFORM operation")
UDP/UDPLITE were blocked as the logic changed to:
if (sk->sk_protocol == IPPROTO_UDP || sk->sk_protocol == IPPROTO_UDPLITE)
	do_some_check;
if (sk->sk_protocol == IPPROTO_TCP)
	do_some_check;

if (sk->sk_protocol != IPPROTO_TCP)
	break;

Fix it by using Eric's code and simply remove the break in TCP check, which
looks like:
if (sk->sk_protocol == IPPROTO_UDP || sk->sk_protocol == IPPROTO_UDPLITE)
	do_some_check;
else if (sk->sk_protocol == IPPROTO_TCP)
	do_some_check;
else
	break;

Fixes: 963166e0162a ("ipv6: fix restrict IPV6_ADDRFORM operation")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>