Description: media: em28xx: Fix use-after-free when disconnecting
References:
 https://source.android.com/security/bulletin/2019-03-01
Notes:
 bwh> Introduced in 3.16 by commit 192292403147 "[media] em28xx: add
 bwh> [2013:025f] PCTV tripleStick (292e)".
Bugs:
upstream: released (4.16-rc1) [910b0797fa9e8af09c44a3fa36cb310ba7a7218d]
4.19-upstream-stable: N/A "Fixed before branching point"
4.9-upstream-stable: released (4.9.143) [6fc74d9f9b412b295f9ad01af7a7e62a662aa5bd]
3.16-upstream-stable: released (3.16.66) [abbb5cf0c8e9995defed43a6c98296f357098b5b]
sid: released (4.16.5-1)
4.9-stretch-security: released (4.9.144-1)
3.16-jessie-security: released (3.16.68-1)