perf tools: Get rid of unused include of config.mak

These lines are came from GIT Makefile and never used for perf.

I found it from make -d output during working on previous patch.

Updating makefiles....
 Considering target file `arch/x86/Makefile'.
 No need to remake target `arch/x86/Makefile'.
 Considering target file `config.mak'.
  File `config.mak' does not exist.
 Must remake target `config.mak'.
 Failed to remake target file `config.mak'.
 Considering target file `config.mak.autogen'.
  File `config.mak.autogen' does not exist.
 Must remake target `config.mak.autogen'.
 Failed to remake target file `config.mak.autogen'.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1358337594-10916-2-git-send-email-namhyung@kernel.org


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