libusbhost: Fix IOCTL call during usb_request_cancel

USBDEVFS_DISCARDURB IOCTL call expects a pointer to the
the urb structure to be passed from userspace. LibusbHost
instead sends usbdevfs_urb**. Change this to usbdevfs_urb*.

Fixes Issue: https://code.google.com/p/android/issues/detail?id=74530

Change-Id: Ifb8a13857e1a9f62536f2a07c0965e9c419b7d4c
1 file changed