sctp: remove useless arguments from get_saddr() call

There is no point in passing a destination address to
a get_saddr() call.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>