The 'p' member of struct sctp_paramhdr is common part for
IPv4 addr parameter and IPv6 addr parameter in union sctp_addr_param.

For addr-related code, use specified addr parameter.
Otherwise, use common header to access type/length member.
Signed-off-by: NShan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>