perf events parse: Rename parse_events_parse arguments

perf events parse: Rename parse_events_parse arguments

Calling them just "data" is too vague, call it 'perf_state', to make it
clearer, for instance, when looking at patch hunks.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-rnhk5yb05wem77rjpclrh7so@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>