c37e2d38d6
A zero "FeatureControlValue" currently means "no feature control, or feature control with zero value". Distinguish both cases by explicitly recording the presence of the "etc/msr_feature_control" fw_cfg file. This will be helpful later in this series, when we won't want to touch fw_cfg again, but still know if "etc/msr_feature_control" was read OK. Signed-off-by: Laszlo Ersek <laszlo.ersek@posteo.net>