#280 support more than 24 events for ocount/operf

[Paul A. Clarke]

I believe if the number of events specified is greater than the number architecturally permitted, ocount/operf will multiplex the events to allow for a simulated larger number of concurrent events. However, there is an (arbitrary?) limit of 24:
$ ocount -e $(ophelp | grep ^PM_ | cut -f1 -d: | tr '\n' ,) ls
Number of events specified is greater than allowed maximum of 24.
$ ocount --version
ocount: oprofile 1.2.0git compiled on Feb 4 2016 10:52:27

This request is to allow for specifying more than 24 "simultaneous" events with ocount/operf.