perf tools: Pass tool context in the the perf_event_ops functions

So that we don't need to have that many globals.

Next steps will remove the 'session' pointer, that in most cases is
not needed.

Then we can rename perf_event_ops to 'perf_tool' that better describes
this class hierarchy.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-wp4djox7x6w1i2bab1pt4xxp@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index 899080a..f06b0a4 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -845,7 +845,8 @@
 		die("Unknown type of information\n");
 }
 
-static int process_sample_event(union perf_event *event,
+static int process_sample_event(struct perf_event_ops *ops __used,
+				union perf_event *event,
 				struct perf_sample *sample,
 				struct perf_evsel *evsel __used,
 				struct perf_session *s)