Add linux-um archives to lore.kernel.org?

[Bjorn Helgaas]

The linux-um@xxxxxxxxxxxxxxxxxxx mailing list is listed in MAINTAINERS
and is quite active [1].  Once in a while a commit links to the
infradead pipermail archive [2] (the link in that commit appears
broken).

I propose that we add linux-um to the lore.kernel.org archives so
future commits can use lore.kernel.org links that don't depend on
infradead.

https://korg.docs.kernel.org/lore.html says pipermail archives like
infradead has are not ideal, but I don't have any archives at all, and
I don't know how to get even pipermail archives out of infradead.

Bjorn

[1] http://lists.infradead.org/pipermail/linux-um/
[2] https://git.kernel.org/linus/3b0b42527937