linux/libusb: do not check bDeviceClass on enumeration

Some composite devices may not have bDeviceClass set to LIBUSB_CLASS_PER_INTERFACE
and so will be ignored when enumerating HID devices.

Ignore checking the bDeviceClass as we will be checking interface bInterfaceClass
later anyway.

Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>