sysctl: Remove CTL_NONE and CTL_UNNUMBERED

Now that the sysctl structures no longer have a ctl_name field
there is no reason to retain the definitions for CTL_NONE and
CTL_UNNUMBERED, or to explain their historic usage.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

Documentation/sysctl/ctl_unnumbered.txt

-
-Except for a few extremely rare exceptions user space applications do not use
-the binary sysctl interface.  Instead everyone uses /proc/sys/...  with
-readable ascii names.
-
-Recently the kernel has started supporting setting the binary sysctl value to
-CTL_UNNUMBERED so we no longer need to assign a binary sysctl path to allow
-sysctls to show up in /proc/sys.
-
-Assigning binary sysctl numbers is an endless source of conflicts in sysctl.h,
-breaking of the user space ABI (because of those conflicts), and maintenance
-problems.  A complete pass through all of the sysctl users revealed multiple
-instances where the sysctl binary interface was broken and had gone undetected
-for years.
-
-So please do not add new binary sysctl numbers.  They are unneeded and
-problematic.
-
-If you really need a new binary sysctl number please first merge your sysctl
-into the kernel and then as a separate patch allocate a binary sysctl number.
-
-(ebiederm@xmission.com, June 2007)

include/linux/sysctl.h

@@ -15,9 +15,6 @@
  **  The kernel will then return -ENOTDIR to any application using
  **  the old binary interface.
  **
- **  For new interfaces unless you really need a binary number
- **  please use CTL_UNNUMBERED.
- **
  ****************************************************************
  ****************************************************************
  */
@@ -50,12 +47,6 @@ struct __sysctl_args {
 
 /* Top-level names: */
 
-/* For internal pattern-matching use only: */
-#ifdef __KERNEL__
-#define CTL_NONE	0
-#define CTL_UNNUMBERED	CTL_NONE	/* sysctl without a binary number */
-#endif
-
 enum
 {
 	CTL_KERN=1,		/* General kernel info and control */