net: qrtr: Fix error pointer vs NULL bugs

The callers only expect NULL pointers, so returning an error pointer
will lead to an Oops.

Fixes: 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace")
Signed-off-by: Dan Carpenter <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/qrtr/ns.c

···
 	/* If node didn't exist, allocate and insert it to the tree */
 	node = kzalloc(sizeof(*node), GFP_KERNEL);
 	if (!node)
-		return ERR_PTR(-ENOMEM);
+		return NULL;
 
 	node->id = node_id;
 
···
 
 	srv = kzalloc(sizeof(*srv), GFP_KERNEL);
 	if (!srv)
-		return ERR_PTR(-ENOMEM);
+		return NULL;
 
 	srv->service = service;
 	srv->instance = instance;