perf auxtrace: Uninline functions that touch perf_session

So that we don't carry the session.h include directive in auxtrace.h,
which in turn opens a can of worms of files that were getting all sorts
of things via that include, fix them all.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-d2d83aovpgri2z75wlitquni@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/cs-etm.h b/tools/perf/util/cs-etm.h
index bc848fd..650ecc2 100644
--- a/tools/perf/util/cs-etm.h
+++ b/tools/perf/util/cs-etm.h
@@ -8,9 +8,10 @@
 #define INCLUDE__UTIL_PERF_CS_ETM_H__
 
 #include "util/event.h"
-#include "util/session.h"
 #include <linux/bits.h>
 
+struct perf_session;
+
 /* Versionning header in case things need tro change in the future.  That way
  * decoding of old snapshot is still possible.
  */