bq2415x_charger: Fix null pointer dereference

Commit b68c316 (bq2415x_charger: Allow to load and use driver even if
notify device is not registered yet) introduced null pointer dereference in
case bq is NULL. This patch fixes it.

Fixes: b68c316 ("bq2415x_charger: Allow to load and use driver even if notify device is not registered yet")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>

drivers/power/bq2415x_charger.c

@@ -1704,7 +1704,7 @@ static int bq2415x_probe(struct i2c_client *client,
 error_3:
 	bq2415x_power_supply_exit(bq);
 error_2:
-	if (bq->notify_node)
+	if (bq && bq->notify_node)
 		of_node_put(bq->notify_node);
 	kfree(name);
 error_1: