let's use usb_find_common_endpoints() to discover endpoints, it does all
necessary checks for type and xfer direction

remove memset() in hfa384x_create(), because we now assign endpoints in
prism2sta_probe_usb() and because create_wlan() uses kzalloc() to
allocate hfa384x struct before calling hfa384x_create()

Fixes: faaff976 ("staging: wlan-ng: properly check endpoint types")
Reported-and-tested-by: syzbot+22794221ab96b0bab53a@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=22794221ab96b0bab53aSigned-off-by: Rustam Kovhaev <rkovhaev@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200804145614.104320-1-rkovhaev@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>