[S390] perf: add support for s390x CPU counters

Add a perf PMU to access the CPU-measurement counter facility CPUM CF.
CPUM CF provides multiple counter sets for measuring generic,
problem-state, and crypto activaties.  Also an extended counter set for
the IBM System z10 and IBM z196 mainframes is available.

Counters from the basic and problem-state counter set are mapped to
generic perf hardware events.  Other counters are accessible through
raw events.

For a list of available counter sets and counters, see:

  - The Load-Program-Parameter and the CPU-Measurement Facilities (SA23-2260)
  - The CPU-Measurement Facility Extended Counters Definition for
    z10 and z196 (SA23-2261)

Reviewed-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>