perf report: Force tty output if -T/--thread option is given

perf report: Force tty output if -T/--thread option is given

The -T/--thread option is supported only on --stdio mode (at least for
now).  So enforce the tty output if the option was requested.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1431184784-30525-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>