perf tools: Honor parallel jobs

We need to hand down parallel build options like the internal make
--jobserver-fds one so that parallel builds can also happen when
building perf from the toplevel directory.

Make it so #1!

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1361374353-30385-3-git-send-email-bp@alien8.de


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