drivers: watchdog: exar_wdt.c fix use after free

fix use after free by storing the result of PTR_ERR(n->pdev)
to a local variable before returning.

Signed-off-by: Manank Patel <[email protected]>
Reviewed-by: Guenter Roeck <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Guenter Roeck <[email protected]>
Signed-off-by: Wim Van Sebroeck <[email protected]>

Author: manank20

drivers/watchdog/exar_wdt.c

@@ -355,8 +355,10 @@ static int __init exar_wdt_register(struct wdt_priv *priv, const int idx)
 						    &priv->wdt_res, 1,
 						    priv, sizeof(*priv));
 	if (IS_ERR(n->pdev)) {
+		int err = PTR_ERR(n->pdev);
+
 		kfree(n);
-		return PTR_ERR(n->pdev);
+		return err;
 	}
 
 	list_add_tail(&n->list, &pdev_list);