sctp: force SCTP_ERROR_INV_STRM with __u32 when calling sctp_chunk_fail

This patch is to force SCTP_ERROR_INV_STRM with right type to
fit in sctp_chunk_fail to avoid the sparse error.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>