perf annotate: Add --symfs option

If you have --symfs in perf report, then you also need it for perf
annotate.  This allows off-box assembly level analysis of perf.data
samples.

This patch complements:

commit ec5761ea
Author: David Ahern <daahern@cisco.com>
Date:   Thu Dec 9 13:27:07 2010 -0700

    perf symbols: Add symfs option for off-box analysis using specified tree

Acked-by: David Ahern <daahern@cisco.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Ahern <daahern@cisco.com>
Link: http://lkml.kernel.org/r/20110729232040.GA21838@quad


Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>