sysctl: Remove superfluous includes from kernel/sysctl.c

Remove the following headers from the include list in sysctl.c.

* These are removed as the related variables are no longer there.
  ===================   ====================
  Include               Related Var
  ===================   ====================
  linux/kmod.h          usermodehelper
  asm/nmi.h             nmi_watchdoc_enabled
  asm/io.h              io_delay_type
  linux/pid.h           pid_max_{,min,max}
  linux/sched/sysctl.h  sysctl_{sched_*,numa_*,timer_*}
  linux/mount.h         sysctl_mount_max
  linux/reboot.h        poweroff_cmd
  linux/ratelimit.h     {,printk_}ratelimit_state
  linux/printk.h        kptr_restrict
  linux/security.h      CONFIG_SECURITY_CAPABILITIES
  linux/net.h           net_table
  linux/key.h           key_sysctls
  linux/nvs_fs.h        acpi_video_flags
  linux/acpi.h          acpi_video_flags
  linux/fs.h            proc_nr_files

* These are no longer needed as intermediate includes
  ==============
  Include
  ==============
  linux/filter.h
  linux/binfmts.h

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Joel Granados <joel.granados@kernel.org>