Kernel prepatch 6.15-rc6

Linus has released 6.15-rc6 for testing.

Everything still looks fairly normal - we've got a bit more commits
than we did in rc5, which isn't the trend I want to see as the
release progresses, but the difference isn't all that big and it
feels more like just the normal noise in timing fluctuation in pull
requests of fixes than any real signal.

So I won't worry about it. We've got another two weeks to go in the
normal release schedule, and it still feels like everything is on
track.