Merge branch 'core/speculation' of git://git.kernel.org/pub/scm/linux/kernel/git...

Pull in core support for the "mitigations=" cmdline option from Thomas
Gleixner via -tip, which we can build on top of when we expose our
mitigation state via sysfs.

diff --cc Documentation/admin-guide/kernel-parameters.txt
Simple merge

diff --cc arch/powerpc/kernel/security.c
Simple merge

diff --cc arch/powerpc/kernel/setup_64.c
Simple merge

diff --cc arch/x86/kernel/cpu/bugs.c
Simple merge

diff --cc arch/x86/mm/pti.c
Simple merge

diff --cc kernel/cpu.c
Simple merge