Sorry for the noob question, how would I submit this fix?

There are two documents for you to read:

https://docs.kernel.org/process/submitting-patches.html

https://www.kernel.org/doc/html/latest/process/maintainer-netdev.html

Since this is a fix, please use the net tree. And include a Fixes: tag
indicating the patch which broke it.

Just commit and separately git send-email to netdev@vger.kernel.org?

./scripts/get_maintainer.pl will give you a list of email addresses.

Or take a look at

https://b4.docs.kernel.org/en/latest/contributor/prep.html

b4 automates some of the steps in producing patches, keeping track of
versions, working out who to send to etc.

Often with the kernel, the code is easy. Getting the processes correct
is harder. But we are here to help.

	  Andrew