This moves all the options under a proper menu.

Based on a patch from Randy Dunlap.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>