[c-nsp] Stratum 0 PPS Hardware clock compatibility

[Jason Gurtz]

I have found a lot of documentation online that states the 7200 is the
only Cisco device that supports a PPS hardware clock via the Aux port.  I
see recommendations for Trimble Acutime 2000 since replaced by mfr. and
other solutions but these documents are a few years old.  Has this feature
been added to other platforms such as the 6500 series?

~JasonG