Description: media: videobuf2-v4l2: drop WARN_ON in vb2_warn_zero_bytesused()
References:
 https://source.android.com/security/bulletin/pixel/2019-09-01
Notes:
 bwh> Introduced in 4.1 by commit f61bf13b6a07 "[media] vb2: add
 bwh> allow_zero_bytesused flag to the vb2_queue struct".
Bugs:
upstream: released (5.0-rc1) [5e99456c20f712dcc13d9f6ca4278937d5367355]
4.19-upstream-stable: released (4.19.31) [573d423a9bd76b396954ddf847ff24d97658453d]
4.9-upstream-stable: released (4.9.165) [7f422aa63d5a0905232455a8953cd9bc02eab4da]
3.16-upstream-stable: N/A "Vulnerable code not present"
sid: released (4.19.37-1)
4.19-buster-security: N/A "Fixed before branching point"
4.9-stretch-security: released (4.9.168-1)
3.16-jessie-security: N/A "Vulnerable code not present"