By specifying "BROKEN := 1" or "BROKEN := y" for a device, it will be
hidden (and deselected) by default. By that, it provides a stronger
option to "disable" a device beyond just using DEFAULT := n.
To make these devices visible, just enable the BROKEN option in
developer settings as already implemented for targets and packages.
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>