MFC r246616 and r246759:

- Move scratch data from the USB bus structure to the USB device
structure so that simultaneous access cannot happen. Protect scratch
area using the enumeration lock.
- Reduce stack usage in usbd_transfer_setup() by moving some big stack
members to the scratch area. This saves around 200 bytes of stack.
- Fix a whitespace.
- Protect control requests using the USB device enumeration lock.
- Make sure all callers of usbd_enum_lock() check the return value.
- Remove the control transfer specific lock.
- Bump the FreeBSD version number, hence external USB modules may need
to be recompiled due to a USB device structure change.


git-svn-id: svn+ssh://svn.freebsd.org/base/stable/8@247091 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f