Hi

Working on a system which did not have a USB in it. I was getting a
segfault with hid2hci. The problem tracked down was usb_init () was 
failing and we did not check for it and carried on with execution. 
As a result the next call to libusb failed because we passed in NULL for
ctx because during usb_init () this should have been malloc'ed if all
have gone correctly but in case of error usb_init () free's up the
allocated memory and hence the segfault. 

We should check for return value of usb_init () call and exit
immediately if it fails. Tested on 4.24 release. 

OK ?

Thanks

-Khem