perf annotate: Fix perf top module symbol annotation

Signed-off-by: Mike Galbraith <efault@gmx.de>
Cc: Kirill Smelkov <kirr@landau.phys.spbu.ru>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1265265106.6364.5.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>