platform/chrome: pstore: probe for ramoops buffer using acpi

In order to handle the firmware placing the ramoops buffer
in a different location than the kernel is configured to look
probe for an ACPI device specified by GOOG9999 acpi id. If
no device is found or the first memory resource is not defined
properly fall back to the configured base and length.

Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Signed-off-by: Ben Zhang <benzh@chromium.org>
Signed-off-by: Filipe Brandenburger <filbranden@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Olof Johansson <olofj@chromium.org>
Signed-off-by: Olof Johansson <olof@lixom.net>