Add the IFD regions as child devices and set the region access on the child
devices. Also add read-only SPI descriptor as an HSI attribute and require
FLOCKDN on Intel hardware.
Use the hidden PCI 00:1f.5 device to set the SPIBAR automatically and generate
the quirk file automatically to support more hardware.
The clients don't need to know this, and exporting them means we paint-ourselves
into a corner if we want to change the 'namespace' or how HSI actually works.
