perf record: Synthesize unit/scale/... in event update

perf record: Synthesize unit/scale/... in event update

Move the code to synthesize event updates for scale/unit/cpus to a
common utility file, and use it both from stat and record.

This allows to access scale and other extra qualifiers from perf script.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20171117214300.32746-2-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>