hwpmc support for Intel IceLake desktop and server processors

[siderop1_netapp.com]

Summary

This change adds PMU event definitions for the Ice Lake Xeon processor and updates the HWPMC device to detect and support the microarchitecture.

[siderop1_netapp.com]

Barf. Looks like this was already implemented with 913c07a0499, but I failed to sync past that in my Git repo. I'll revisit if I find any differences worth submitting.
--ap