illumos gate

Per RFD 137 (https://github.com/joyent/rfd/blob/master/rfd/0137/README.md) we'd like to be able to implement CPU based autoreplace based on the Intel PPIN functionality when available in the system. This change covers adding the ability to detect that and adds support to FM to include this synthesized serial number as a serial number.

One important side effect of this as per the RFD is that we need to make sure that we don't consider the CPU FMRI replaced unless both the faulted and non-faulted versions both have a valid synthesized serial number.

To test this I injected faults in a number of different circumstances and switched platforms images between versions before this change, those with this change and the normal ID, those with this change and the ID disabled, and those with this change and a forcibly overwritten ID.

The different cases we tested were:

Pre-change -> Pre-change (fault persists)
    post w/ label -> post w/o label (fault persists)
    Post w/label -> pre-change (fault persists)
    post w/label -> post w/ same label (fault persists)
    Post w/label -> Post w/ new label (fault clears)
    Post w/label -> post w/o label -> post w/ same label (fault persists)
    Post w/label -> post w/o label -> post w/ new label (fault clears)
    Post w/o label -> pre w/o label -> post w/label (fault persists)

I also went through and tested what happened when the BIOS locks this as was the case on certain platforms.