cxl: Use to_pci_driver() instead of pci_dev->driver

Struct pci_driver contains a struct device_driver, so for PCI devices, it's
easy to convert a device_driver * to a pci_driver * with to_pci_driver().
The device_driver * is in struct device, so we don't need to also keep
track of the pci_driver * in struct pci_dev.

Replace pdev->driver with to_pci_driver(). This is a step toward removing
pci_dev->driver.

[bhelgaas: split to separate patch]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Uwe Kleine-König <[e-mail]>
Signed-off-by: Bjorn Helgaas <[e-mail]>

drivers/misc/cxl/guest.c

···
 		return;
 
 	list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {
-		afu_drv = afu_dev->driver;
+		afu_drv = to_pci_driver(afu_dev->dev.driver);
 		if (!afu_drv)
 			continue;
 

drivers/misc/cxl/pci.c

···
 		return result;
 
 	list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {
-		afu_drv = afu_dev->driver;
+		afu_drv = to_pci_driver(afu_dev->dev.driver);
 		if (!afu_drv)
 			continue;
 
···
 			 * shouldn't start new work until we call
 			 * their resume function.
 			 */
-			afu_drv = afu_dev->driver;
+			afu_drv = to_pci_driver(afu_dev->dev.driver);
 			if (!afu_drv)
 				continue;
 
···
 			continue;
 
 		list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {
-			afu_drv = afu_dev->driver;
+			afu_drv = to_pci_driver(afu_dev->dev.driver);
 			if (!afu_drv)
 				continue;