[SCTP] Use ipv6_addr_any() rather than ipv6_addr_type() in sctp_v6_is_any().

Signed-off-by: Brian Haley <Brian.Haley@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>