net/sctp: Prevent autoclose integer overflow in sctp_association_init()

In the Linux kernel, the following vulnerability has been resolved: net/sctp: Prevent autoclose integer overflow in sctp_association_init() While by default max_autoclose equals to INT_MAX / HZ, one may set net.sctp.max_autoclose to UINT_MAX. There is code in sctp_association_init() that can consequently trigger overflow.