vfio: use match_string() helper

match_string() returns the index of an array for a matching string,
which can be used intead of open coded variant.

Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: kvm@vger.kernel.org
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/vfio.c

@@ -630,8 +630,6 @@ static const char * const vfio_driver_whitelist[] = { "pci-stub" };
 
 static bool vfio_dev_whitelisted(struct device *dev, struct device_driver *drv)
 {
-	int i;
-
 	if (dev_is_pci(dev)) {
 		struct pci_dev *pdev = to_pci_dev(dev);
 
@@ -639,12 +637,9 @@ static bool vfio_dev_whitelisted(struct device *dev, struct device_driver *drv)
 			return true;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(vfio_driver_whitelist); i++) {
-		if (!strcmp(drv->name, vfio_driver_whitelist[i]))
-			return true;
-	}
-
-	return false;
+	return match_string(vfio_driver_whitelist,
+			    ARRAY_SIZE(vfio_driver_whitelist),
+			    drv->name) >= 0;
 }
 
 /*