perf tools: Kbuild source related fixies

Fixing several sources config dependencies to allow
separate config builds.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Cc: Stephane Eranian <eranian@google.com>
perf tools: Add kbuild support into Makefile.kbuild

Adding kbuild support into Makefile.kbuild. The 'legacy'
Makefile still stays untouched as it was.

It's possible to use kbuild by running 'make -f Makefile.kbuild'
with any option supported by 'legacy' Makefile.

We now have 2 config files:
  '.config' - user configured setup
  '.config-detected' - system detected setup

The '.config-detected' affects '.config' and if there's
configured feature in '.config' which was not detected
it is automatically disabled.

The '.config-detected' is re/created if:
  - there's no '.config-detected'
  - '.config' was changed

In a cleaned tree the perf is built with 'allyesconfig'
having disabled all non-detected features, just as it is
done now.

You can change '.config' via:
  make -f Makefile.kbuild menuconfig

There's difference for O=DIR build. The DIR is populated
based on kernel source tree, so the final binary is created
under DIR/tools/perf.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Cc: Stephane Eranian <eranian@google.com>
perf kbuild: fix recursive invocation of config/features-checks