Search for the '/backlight' node to determine if backlight control is available instead of looking for the backlight-control attribute. Fixes backlight control on some apple laptops.
Search for the '/backlight' node to determine if backlight control is
available instead of looking for the backlight-control attribute.
Fixes backlight control on some apple laptops.

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars