perf tools: Convert invocation of MAKE into SUBDIR

This will show directory change info in a consistent form.  Also it can
be converted again into David Howell's descend command.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Borislav Petkov <bp@amd64.org>
Cc: David Howells <dhowells@redhat.com>
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/1351241752-2919-3-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>