perf cpuid: Introduce a platform specific cpuid compare function

perf cpuid: Introduce a platform specific cpuid compare function

The function get_cpuid_str() is called by perf_pmu__getcpuid() and on
s390 returns a complete description of the CPU and its capabilities,
which is a comma separated list.

To map the CPU type with the value defined in the
pmu-events/arch/s390/mapfile.csv, introduce an architecture specific
cpuid compare function named strcmp_cpuid_str()

The currently used regex algorithm is defined as the weak default and
will be used if no platform specific one is defined. This matches the
current behavior.

Signed-off-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20180213151419.80737-3-tmricht@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>