[PATCH 1/2 -tip] perf: Keep track of remaining time when enabling/disabling swevent hrtimers

[Soeren Sandmann]

[I don't think this mail got through the first time]

Hi,

These patches against perf/core make the hrtimer based events work for
sysprof.

1/2: Don't restart the timer on every scheduler tick
2/2: If exclude_idle is set, don't report idle events

Thanks,                                                                         
Soren