tools/testing/cxl: Use dev_is_platform()

Use dev_is_platform() instead of checking bus type directly.
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://patch.msgid.link/20240827095123.168696-1-kunwu.chan@linux.devSigned-off-by: Dave Jiang <dave.jiang@intel.com>

tools/testing/cxl/mock_acpi.c

@@ -18,7 +18,7 @@ struct acpi_device *to_cxl_host_bridge(struct device *host, struct device *dev)
 		goto out;
 	}
 
-	if (dev->bus == &platform_bus_type)
+	if (dev_is_platform(dev))
 		goto out;
 
 	adev = to_acpi_device(dev);