On some architecture the size of the private header may be dependent on
the number of tracers used in the session.  As such adding a "struct
perf_evlist *" parameter, which should contain all the required
information.

Also adjusting the existing client of the interface to take the new
parameter into account.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Grant <al.grant@arm.com>
Cc: Chunyan Zhang <zhang.chunyan@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Cc: Mike Leach <mike.leach@arm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rabin Vincent <rabin@rab.in>
Cc: Tor Jeremiassen <tor@ti.com>
Link: http://lkml.kernel.org/r/1452807977-8069-22-git-send-email-mathieu.poirier@linaro.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>