perf tools: Add event_update event scale type

perf tools: Add event_update event scale type

A__allocdding scale type 'event update' event, that stores/transfer
events scale value. The PMU events can define the scale
value which is used to multiply events data.

Signed-off-by: Jiri Olsa <[email protected]>
Tested-by: Kan Liang <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>