fix failure of pthread_setschedparam to pass correct param to kernel

the address of the pointer, rather than the pointer, was being passed.
this was probably a copy-and-paste error from corresponding get code.

src/thread/pthread_setschedparam.c

@@ -4,7 +4,7 @@ int pthread_setschedparam(pthread_t t, int policy, const struct sched_param *par
 {
 	int r;
 	__lock(t->killlock);
-	r = t->dead ? ESRCH : -__syscall(SYS_sched_setscheduler, t->tid, policy, &param);
+	r = t->dead ? ESRCH : -__syscall(SYS_sched_setscheduler, t->tid, policy, param);
 	__unlock(t->killlock);
 	return r;
 }