perf mem: Document incorrect and missing options

Several options were incorrectly described, some lacked describing
required arguments while others were simply not documented, fix it.

Signed-off-by: Sangwon Hong <qpakzk@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Taeung Song <treeze.taeung@gmail.com>
Link: http://lkml.kernel.org/r/1524382146-19609-1-git-send-email-qpakzk@gmail.com


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