Linux 4.15 rc7

Ok, we had an interesting week, and by now everybody knows why we were
merging all those odd x86 page table isolation patches without
following all of the normal release timing rules.
But rc7 itself is actually pretty calm. Yes, there were a few small
follow-up patches to the PTI code still, and yes, there's been a fair
amount of discussion about the exact details of the Spectre fixes, but
at least in general things have been nice and calm. And we're actually
back to "normal" in that most of the patches are drivers (mainly GPU,
some crypto, some random small things - input layer, platform drivers
etc). There are misc small filesystem and arch updates too.

The appended shortlog is small enough that it's easy to just scroll
down and get a feel for what happened.

The one thing I want to do now that Meltdown and Spectre are public,
is to give a *big* shout-out to the x86 people, and Thomas Gleixner in
particular for really being on top of this.  It's been one huge
annoyance, and honestly, Thomas really went over and beyond in this
whole mess.  A lot of other people have obviously been involved too,
don't get me wrong, but this is exactly the kind of issue that easily
results in lots of nasty hacky patches because people are falling all
over themselves trying to fix it and they can't even talk about why
they are doing it in public, and Thomas &co ended up being a huge
reason for why it was all much easier for me to merge: because of the
literally _months_ of work on quality control and gating these patches
and making sure the end result was a clean and manageable series.

So a big *BIG* thanks to Thomas for making it so much easier for me to
merge all this stuff.  The whole nasty TLB isolation patches would
have been just _so_ much more horrible without him.

Anyway, due to this all, 4.15 will obviously be one of the releases
with an rc8, even if things are starting to really calm down by now.
We'll see, hopefully we won't need any more than that.