This adds support for the NVRAM handling and the basic SPROM
hardware used on siba(4) and bcma(4) devices, including:
- SPROM directly attached to the PCI core, accessible via PCI configuration space.
- SPROM attached to later ChipCommon cores.
- SPROM variables vended from the parent SoC bus (e.g. via a directly-attached flash device).
Additional improvements to the NVRAM/SPROM interface will
be required, but this changeset stands alone as working
checkpoint.
Depends on D6195