sctp: fix error return code in sctp_sendmsg_new_asoc()

Return error code -EINVAL in the address len check error handling
case since 'err' can be overwrite to 0 by 'err = sctp_verify_addr()'
in the for loop.

Fixes: 2c0dbaa0 ("sctp: add support for SCTP_DSTADDRV4/6 Information for sendmsg")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>