perf: Intel uncore pmu counting support

Hi, all

I posted uncore patches months ago, but it was pended due to an uncore
interrupt problem.

This series are cut to support uncore pmu counting only.
So uncore interrupt handling is not needed.

The uncore pmu type is allocated dynamically and exported via sysfs.
$ cat /sys/bus/event_source/devices/uncore/type
6

You can count uncore raw events as below,
$ perf stat -e uncore:r0101 ls

It reads uncore pmu type id from sysfs to setup perf_event_attr::type.

Comments are appreciated.

Thanks,
Lin Ming