Memory allocated from parent queue was freed/added to chained queue.

Issue was seen with below example
EventQueue q1;
EventQueue q2;

void main() {
while( true ) {
q1.chain( &q2 ); // Chain q2 to q1
q1.chain( NULL ); // Remove chain from q1
//This second step should free the memory from the chained q2 event.
}
}

Memory allocated from q1 slab was freed for q2, which will result in
memory leak.

events/equeue/equeue.c

@@ -601,7 +601,7 @@ static void equeue_chain_update(void *p, int ms)
     if (ms >= 0) {
         c->id = equeue_call_in(c->target, ms, equeue_chain_dispatch, c->q);
     } else {
-        equeue_dealloc(c->target, c);
+        equeue_dealloc(c->q, c);
     }
 }