[$] The boot-constraint subsystem

Thefifth version of the patch series addingthe boot-constraint subsystem is under review on the linux-kernel mailing list. The purpose of this subsystem is tohonor the constraints put on devices by thebootloader before those devices arehanded over to the operating system (OS) - Linux in our case. If theseconstraints are violated, devices may fail to work properly once the kernelstarts reconfiguring the hardware; by tracking and enforcing thoseconstraints, instead, we can ensure that hardware continues to workproperly until the kernel is fully operational.