Linux 4.16 rc6

This has been a nice quiet week, so rc6 is pretty tiny. Everything
looks like we're on a usual schedule - I'll make an rc7, but hopefully
that will be it.

Mostly driver changes (usb, gpu, sound, scsi, md), but it's all tiny.
Some arch fixes (x86 and microblaze, tiny changes to others), and some
filesystem fixes (a couple of small core vfs fixlets, and some btrfs
and nfs fixes).

Go test, things are stable and there's no reason to worry, but all the
usual reasons to just do a quick build and verification that
everything works for everybody. Ok?