perf sched: Finish latency => atom rename and misc cleanups

perf sched: Finish latency => atom rename and misc cleanups

- Rename 'latency' field/variable names to the better 'atom' ones

 - Reduce the number of #include lines and consolidate them

 - Gather file scope variables at the top of the file

 - Remove unused bits

No change in functionality.

Cc: Peter Zijlstra <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <[email protected]>