perf/x86/intel/uncore: 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/20211004125935.2300113-11-u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

arch/x86/events/intel/uncore.c

@@ -1187,7 +1187,7 @@ static int uncore_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id
 	 * PCI slot and func to indicate the uncore box.
 	 */
 	if (id->driver_data & ~0xffff) {
-		struct pci_driver *pci_drv = pdev->driver;
+		struct pci_driver *pci_drv = to_pci_driver(pdev->dev.driver);
 
 		pmu = uncore_pci_find_dev_pmu(pdev, pci_drv->id_table);
 		if (pmu == NULL)