Linux 5.6 rc4

Hmm. Fairly reasonably sized rc4, and the diffstat looks nice and flat
too (which basically means "lots of small changes") except for a
netfilter ipset fix that ended up being somewhat big and involved due
to locking changes.

That single commit shows up in the dirstat too, and accounts for about
1/6th of the whole patch.

Anyway, everything else looks fairly small. There's a couple of
ethernet drivers that got a few bigger changes, but there really is a
lot of small stuff all over: architectures (x86, arm64, risc-v),
drivers (gpu, hid, networking), filesystems (zonefs and ext4), and
some tracing code.

The shortlog is appended for the people who want to skim the details.