hw/mem/cxl_type3: Add missing copyright and license notice

hw/mem/cxl_type3: Add missing copyright and license notice

This has been missing from the start. Assume it should match
with cxl/cxl-component-utils.c as both were part of early
postings from Ben.

Reported-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Acked-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Fan Ni <fan.ni@samsung.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>