tuntap: correctly set SOCKWQ_ASYNC_NOSPACE

[Nicolas Dichtel]

Hi Ubuntu kernel team,

please, can you consider to cherry-pick the following linux upstream fix:
2f3ab6221e4c ("tuntap: correctly set SOCKWQ_ASYNC_NOSPACE").
It has been included in v4.17 and the patch that introduces the bug has been
included in v4.5.

Here is the launchpad entry:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1830756


Thank you,
Nicolas