mac_nvram: Add block backend to persist NVRAM contents
Add a way to set a backing store for the mac_nvram similar to what
spapr_nvram or mac_via PRAM already does to allow to save its contents
between runs.
Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <
4b1605a9e484cc95f6e141f297487a070fd418ac.
1675297286.git.balaton@eik.bme.hu>
Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>