usb: real freebsd32 support for most ioctls

Use thunks or alternative access methods to support ioctls without
the COMPAT_32BIT hacks that store pointers in uint64_t's on 32-bit
platforms. This should allow a normal i386 libusb to work.

On CheriBSD, the sizes of the structs will differ between CheriABI
(the default) and freebsd64 no matter what so we need proper compat
support there. This change paves the way.

Reviewed by: hselasky, jrtc27 (prior version)