pstate testcase needs update

there are two problems I found, but cannot be fixed easily.
1. in verify_gov_powersave_epp_balance_perf, the default EPP value can be platform specific. But it is out of date.
The kernel quirk lists contains platforms including spr/emr/gnr/gnr-d.
The testcase only contains spr.
2. the hardcoded cpu model check is broken. it didn't check CPU family, and it may break for future platforms with extended family.

It is not an easy fix so I didn't propose any patch.