perf timechart: Remove some needless struct forward declarations

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislav Fomichev <stfomichev@yandex-team.ru>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-jomi6mjv5zi9vsn4vmih5xps@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-timechart.c

@@ -55,14 +55,8 @@ static bool		tasks_only;
 static bool		with_backtrace;
 
 
-struct per_pid;
 struct per_pidcomm;
-
 struct cpu_sample;
-struct power_event;
-struct wake_event;
-
-struct sample_wrapper;
 
 /*
  * Datastructure layout:
@@ -155,7 +149,6 @@ struct wake_event {
 static struct power_event    *power_events;
 static struct wake_event     *wake_events;
 
-struct process_filter;
 struct process_filter {
 	char			*name;
 	int			pid;