perf_counter tools: Share rbtree.with the kernel

perf_counter tools: Share rbtree.with the kernel

The tools/perf/util/rbtree.c copy already drifted by three
csets:

 4b324126e0c6c3a5080ca3ec0981e8766ed6f1ee
 4c60117811171d867d4f27f17ea07d7419d45dae
 16c047add3ceaf0ab882e3e094d1ec904d02312d

So remove the copy and use the lib/rbtree.c directly, sharing
the source code while still generating a separate object file,
since tools/perf uses a far more agressive -O6 switch.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090701152837.GG15682@ghostprotocols.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>