Update to D25266 bin/ps: Make the rtprio option actually show realtime priorities

[mckusick]

Summary

The current ps -o rtprio show threads running at interrupt priority such as the [intr] thread as '1:48' and threads running at kernel priority such as [pagedaemon] as normal:4294967260.

This change shows [intr] as intr:48 and [pagedaemon] as kernel:4.

[kib]

I suspect an idea was that ithreads are real-time threads but with higher priority.