debugfs mount point

personally, i prefer to avoid "nodev" when possible as overuse can result in `mount` output that isnt completely obvious at first ... yes, that info is also available later on, but us english readers scan from left to right and get bored fairly quickly :)

$ mount -t debugfs debugfs /sys/kernel/debug
$ mount | grep debugfs
debugfs on /sys/kernel/debug type debugfs (rw,noexec,nosuid,nodev)