agp: correct missing cleanup on error in agp_add_bridge

While investigating a kmemleak detected leak, I encountered the
agp_add_bridge function.  It appears to be responsible for freeing
the agp_bridge_data in the case of a failure, but it is only doing
so for some errors.

Fix it to always free the bridge data if a failure condition is
encountered.

Signed-off-by: Kevin Winchester <kjwinchester@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/char/agp/backend.c

@@ -285,18 +285,22 @@ int agp_add_bridge(struct agp_bridge_data *bridge)
 {
 	int error;
 
-	if (agp_off)
-		return -ENODEV;
+	if (agp_off) {
+		error = -ENODEV;
+		goto err_put_bridge;
+	}
 
 	if (!bridge->dev) {
 		printk (KERN_DEBUG PFX "Erk, registering with no pci_dev!\n");
-		return -EINVAL;
+		error = -EINVAL;
+		goto err_put_bridge;
 	}
 
 	/* Grab reference on the chipset driver. */
 	if (!try_module_get(bridge->driver->owner)) {
 		dev_info(&bridge->dev->dev, "can't lock chipset driver\n");
-		return -EINVAL;
+		error = -EINVAL;
+		goto err_put_bridge;
 	}
 
 	error = agp_backend_initialize(bridge);
@@ -326,6 +330,7 @@ frontend_err:
 	agp_backend_cleanup(bridge);
 err_out:
 	module_put(bridge->driver->owner);
+err_put_bridge:
 	agp_put_bridge(bridge);
 	return error;
 }