- remove PFM_FL_UNSECURE support because broken
 - remove instrumentation code for syswide ctx update (5% speedup)
 - integrated cleanups from John Levon
 - remove references to pmu_conf.ovfl_val from loops, use local variable
 - updated pfm_bad_permissions()
 - support reset values for non-counting pmds
 - serialization of PFM_RESTART
 - added support for restart_active in per-task mode
 - remove potential deadlock caused by calling pfm_overflow_handler()   from pfm_load_regs()
 - fix invalid check in perfmon_mckinley() for PMC13