Update libusb-1.0.def

Updated by running the following on a libusb-1.0 DLL generated by MinGW32:

echo -e "LIBRARY \"libusb-1.0.dll\"\nEXPORTS" > libusb-1.0.def
strings libusb-1.0.dll | grep ^libusb | grep @ | LC_ALL=C sort | uniq | \
 sed -e "s/\(.*\)@\([0-9]*\)/  \1\n  \1@\2 = \1/" | LC_ALL=C sort >> libusb-1.0.def

Signed-off-by: Tormod Volden <debian.tormod@gmail.com>