libusb: remove use of COMPAT_32BIT

This codepath used uint64_t's in place of pointers in structs and
arrays to allow 32-bit code to use 64-bit version of ioctls. Now
that we support 32-bit compat natively this is no longer needed.

Reviewed by: hselasky, jrtc27 (prior version)

(cherry picked from commit 8010f4ad21b6120e929bda4eed27696e63514677)