PCI/AER: Use guard() in cxl_rch_handle_error_iter()

cxl_rch_handle_error_iter() includes a call to device_lock() using a goto
for multiple return paths. Improve readability and maintainability by
using the guard() lock variant.

Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20260114182055.46029-13-terry.bowman@amd.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

Author: ktbowman

drivers/pci/pcie/aer_cxl_rch.c

@@ -42,11 +42,11 @@ static int cxl_rch_handle_error_iter(struct pci_dev *dev, void *data)
 	if (!is_cxl_mem_dev(dev) || !cxl_error_is_native(dev))
 		return 0;
 
-	device_lock(&dev->dev);
+	guard(device)(&dev->dev);
 
 	err_handler = dev->driver ? dev->driver->err_handler : NULL;
 	if (!err_handler)
-		goto out;
+		return 0;
 
 	if (info->severity == AER_CORRECTABLE) {
 		if (err_handler->cor_error_detected)
@@ -57,8 +57,6 @@ static int cxl_rch_handle_error_iter(struct pci_dev *dev, void *data)
 		else if (info->severity == AER_FATAL)
 			err_handler->error_detected(dev, pci_channel_io_frozen);
 	}
-out:
-	device_unlock(&dev->dev);
 	return 0;
 }