PCI: Extract ATS disabling to a helper function

commit f18b113 upstream.

Introduce quirk_no_ats() helper function to provide a standard way to
disable ATS capability in PCI quirks.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230908143606.685930-2-bartosz.pawlowski@intel.com
Signed-off-by: Bartosz Pawlowski <bartosz.pawlowski@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/pci/quirks.c

@@ -5182,6 +5182,12 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SERVERWORKS, 0x0420, quirk_no_ext_tags);
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SERVERWORKS, 0x0422, quirk_no_ext_tags);
 
 #ifdef CONFIG_PCI_ATS
+static void quirk_no_ats(struct pci_dev *pdev)
+{
+	pci_info(pdev, "disabling ATS\n");
+	pdev->ats_cap = 0;
+}
+
 /*
  * Some devices require additional driver setup to enable ATS.  Don't use
  * ATS for those devices as ATS will be enabled before the driver has had a
@@ -5194,8 +5200,7 @@ static void quirk_amd_harvest_no_ats(struct pci_dev *pdev)
 	    (pdev->device == 0x7341 && pdev->revision != 0x00))
 		return;
 
-	pci_info(pdev, "disabling ATS\n");
-	pdev->ats_cap = 0;
+	quirk_no_ats(pdev);
 }
 
 /* AMD Stoney platform GPU */