hw/nvram/fw_cfg: Use the ldst API

The load/store API eases code review.

Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190309181920.30553-3-philmd@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
1 file changed