cdx: Use mutex guard to simplify error handling

Mutex guard allows to drop one goto/break in error handling and the
less expected code of assigning -EINVAL to unsigned size_t count
variable.

Suggested-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Link: https://patch.msgid.link/20260109-of-for-each-compatible-scoped-v3-7-c22fa2c0749a@oss.qualcomm.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>

Author: krzk

drivers/cdx/cdx.c

@@ -616,18 +616,16 @@ static ssize_t rescan_store(const struct bus_type *bus,
 	if (!val)
 		return -EINVAL;
 
-	mutex_lock(&cdx_controller_lock);
+	guard(mutex)(&cdx_controller_lock);
 
 	/* Unregister all the devices on the bus */
 	cdx_unregister_devices(&cdx_bus_type);
 
 	/* Rescan all the devices */
 	for_each_compatible_node_scoped(np, NULL, compat_node_name) {
 		pd = of_find_device_by_node(np);
-		if (!pd) {
-			count = -EINVAL;
-			goto unlock;
-		}
+		if (!pd)
+			return -EINVAL;
 
 		cdx = platform_get_drvdata(pd);
 		if (cdx && cdx->controller_registered && cdx->ops->scan)
@@ -636,9 +634,6 @@ static ssize_t rescan_store(const struct bus_type *bus,
 		put_device(&pd->dev);
 	}
 
-unlock:
-	mutex_unlock(&cdx_controller_lock);
-
 	return count;
 }
 static BUS_ATTR_WO(rescan);