As last time I wrote “how to find config locations” in kernel menuconfig, there is one more important thing to know. Sometimes kernel options are hidden (and they are even not greppable) because of dependencies.
For example, I tried to turn on CONFIG_USB_SUSPEND but didn’t find it where it shoult be. Here comes another site to help, in current case http://cateee.net/lkddb/web-lkddb/USB_SUSPEND.html. There you find depends on: line, and all you should to do is confirm, that those linked options are also enabled.