perf tools: Get rid of dso__data_fd() from dso__data_size()

perf tools: Get rid of dso__data_fd() from dso__data_size()

It seems that the dso__data_fd() was needed to find a binary type
since open in data_file_size() alone used to fail.

But as it can open the dso fine now, the dso__data_fd() can go away.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
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/1432137821-10853-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>