perf sched timehist: Account thread wait time separately

Separate thread wait time into 3 parts - sleep, iowait and preempt based
on the prev_state of the last event.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170113104523.31212-1-namhyung@kernel.org


[ Fix the build on centos:5 where 'wait' shadows a global declaration ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>