Don't leak an urb in wusb_dev_alloc() if the following kmalloc() failed.
Reported-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NDavid Vrabel <david.vrabel@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>