Description: usb: usbtest: fix missing kfree(dev->buf) in usbtest_disconnect
References:
 https://lkml.org/lkml/2020/6/2/968
Notes:
Bugs:
upstream: released (5.8-rc3) [28ebeb8db77035e058a510ce9bd17c2b9a009dba]
4.19-upstream-stable: needed
4.9-upstream-stable:
3.16-upstream-stable:
sid: needed
4.19-buster-security: needed
4.9-stretch-security:
3.16-jessie-security: