Linux: Fix endianness handling of usbfs config descriptors (#27)

Linux: Fix endianness handling of usbfs config descriptors (#27)

driver/usb/core/devio.c function usbdev_read translate the follwing files
to CPU endianess:

le16_to_cpus(&temp_desc.bcdUSB);
le16_to_cpus(&temp_desc.idVendor);
le16_to_cpus(&temp_desc.idProduct);
le16_to_cpus(&temp_desc.bcdDevice);

All other data is passed without any change.

libusb/os/linux_usbfs.c calls usbi_parse_descriptor with host_endian=1
for config descriptors. According to the kernel code, they must be
processed with host_endian=0, as they are not translated by the kernel.

Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at>