Description: media: vivid: Fix wrong locking that causes race conditions on streaming stop
References:
 https://www.openwall.com/lists/oss-security/2019/11/02/1
 https://lore.kernel.org/lkml/20191102190327.24903-1-alex.popov@linux.com/
 https://lore.kernel.org/lkml/20191103221719.27118-1-alex.popov@linux.com/
Notes:
Bugs:
upstream: released (5.5-rc1) [6dcd5d7a7a29c1e4b8016a06aed78cd650cd8c27]
4.19-upstream-stable: released (4.19.87) [467052f6ea5a51524992e43f02b543550495c391]
4.9-upstream-stable: released (4.9.204) [012a42dbc770d3e815cae536917245d74621c552]
3.16-upstream-stable: N/A "Vulnerable code not present"
sid: released (5.3.15-1)
4.19-buster-security: released (4.19.87-1)
4.9-stretch-security: released (4.9.210-1)
3.16-jessie-security: N/A "Vulnerable code not present"