x86: Move sysctls into arch/x86

Move the following sysctl tables into arch/x86/kernel/setup.c:

  panic_on_{unrecoverable_nmi,io_nmi}
  bootloader_{type,version}
  io_delay_type
  unknown_nmi_panic
  acpi_realmode_flags

Variables moved from include/linux/ to arch/x86/include/asm/ because there
is no longer need for them outside arch/x86/kernel:

  acpi_realmode_flags
  panic_on_{unrecoverable_nmi,io_nmi}

Include <asm/nmi.h> in arch/s86/kernel/setup.h in order to bring in
panic_on_{io_nmi,unrecovered_nmi}.

This is part of a greater effort to move ctl tables into their
respective subsystems which will reduce the merge conflicts in
kerenel/sysctl.c.

Signed-off-by: Joel Granados <joel.granados@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250218-jag-mv_ctltables-v1-8-cd3698ab8d29@kernel.org