Linux 5.7 rc4

Things continue to look normal for the 5.7 release. If anything, rc4
is a bit smaller than usual (it's the smallest rc4 since we had the
tiny one over the Christmas week), and most of the discussions I was
involved with this week were about future development and cleanups
rather than any issues with the current release (although at least in
some cases they were triggered by fixes that came in this release..)

So things seem calm. Although I do suspect that part of "rc4 was
small" is that it's one of those timing things, and there wasn't a
networking pull this week, for example.

The bulk of the rc5 stuff is drivers (gpu, dma, sound, rdma, hyper-v,
md, i2c, mmc) and filesystems (btrfs and nfs).

And misc small fixlets elsewhere.

Anyway, it doesn't feel like there's anything worrisome going on, so
come on in and test the waters..