There are some variable arguments can be specified on make invocation,
but some of them are missing descriptions so that user cannot be
informed easily. Fix it.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1329980894-4289-1-git-send-email-namhyung.kim@lge.comSigned-off-by: Namhyung Kim <namhyung.kim@lge.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>