staging: ti dspbridge: avoid errors if stream id is zero

As 'zero' can be a perfectly good id, it can be picked up as
a NULL from userspace, avoid issues in API and user apps if stream
handle is zero.

Signed-off-by: Ernesto Ramos <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/tidspbridge/pmgr/dspapi.c

···
 {
 	rcu_read_lock();
 	*strmres = idr_find(((struct process_context *)pr_ctxt)->stream_id,
-							(int)hstream);
+							(int)hstream - 1);
 	rcu_read_unlock();
 	return;
 }
···
 	struct strm_res_object *strm_res_obj;
 	struct dsp_streamattrin strm_attr_in;
 	struct node_res_object *node_res;
+	int strmid;
 
 	find_node_handle(&node_res, pr_ctxt, args->args_strm_open.hnode);
 
···
 			   args->args_strm_open.direction,
 			   args->args_strm_open.index, &attr, &strm_res_obj,
 			   pr_ctxt);
-	CP_TO_USR(args->args_strm_open.ph_stream, &strm_res_obj->id, status, 1);
+	if (!status) {
+		strmid = strm_res_obj->id + 1;
+		CP_TO_USR(args->args_strm_open.ph_stream, &strmid, status, 1);
+	}
 	return status;
 }