Update of Documentation/00-INDEX

Update of Documentation/00-INDEX

Added files
- hsi.txt was added by 3a8ab8af (HSI: Add some general description for
  the HSI subsystem)
- lzo.txt was added by d98a0526 (lzo: document part of the encoding)
- xillybus.txt was added by 7051924f (xillybus: Move out of staging)
- mailbox.txt was added by 15320fbc (add documentation for mailbox
  framework)

Moved files
- xommit 214e0aed (Move locking related docs into Documentation/locking/):
  * lockdep-design.txt
  * lockstat.txt
  * mutex-design.txt
  * rt-mutex-design.txt
  * rt-mutex.txt
  * spinlocks.txt
  * ww-mutex-design.txt
- kselftest.txt was moved by 3c415707 (kselftest: Move the docs to the
  Documentation dir)

CC: Davidlohr Bueso <davidlohr@hp.com>
CC: Willy Tarreau <w@1wt.eu>
CC: Randy Dunlap <rdunlap@infradead.org>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Sebastian Reichel <sre@kernel.org>
CC: Eli Billauer <eli.billauer@gmail.com>
CC: Jonathan Corbet <corbet@lwn.net>
CC: Jiri Kosina <trivial@kernel.org>
CC: linux-doc@vger.kernel.org
CC: linux-kernel@vger.kernel.org
Cc: Tim Bird <tim.bird@sonymobile.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Henrik Austad <henrik@austad.us>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>