devres: use to_pci_dev()

Use to_pci_dev() instead of open-coding it.
Signed-off-by: Geliang Tang <geliangtang@163.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

lib/devres.c

@@ -236,7 +236,7 @@ struct pcim_iomap_devres {
 
 static void pcim_iomap_release(struct device *gendev, void *res)
 {
-	struct pci_dev *dev = container_of(gendev, struct pci_dev, dev);
+	struct pci_dev *dev = to_pci_dev(gendev);
 	struct pcim_iomap_devres *this = res;
 	int i;