perf c2c report: Add -f/--force option

perf c2c report: Add -f/--force option

Adding -f/--force option to go through ownership validation:

  $ sudo perf c2c report
  File perf.data not owned by current user or root (use -f to override)
  $
  $ sudo perf c2c report -f
  < c2c report output >
  $

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1479764011-10732-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>