* Added perf_event_header definition

* Added perf_event_mmap_page definition

* Removed default values for perf_event_header

* Fixed comments typos

* Updated perf_event_attr definition

* Explicit packet struct type

* PERF.RECORD from struct to enum

* fix typo: miscs to misc

* misc as packed struct

* cpu_mode as named enum

* Rescoping CPU_MODE