[$] 4.20 Merge window part 2

At the end of the 4.20 merge window, 12,125 non-merge
changesets had been pulled into the mainline kernel repository; 6,390 came
in since last week's summary was written.
As is often the case, the latter part of the merge window contained a
larger portion of cleanups and fixes, but there were a number of new
features in the mix as well.