tools: move accounting tool from Documentation

Move accounting tool to tools and remove it from Documentation
Makefile. Update location information for this tool. Create a
new Makefile to build accounting. It can be built from top level
directory or from accounting directory:

Run make -C tools/accounting or cd tools/accounting; make

Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
diff --git a/Documentation/accounting/delay-accounting.txt b/Documentation/accounting/delay-accounting.txt
index 8a12f07..042ea59 100644
--- a/Documentation/accounting/delay-accounting.txt
+++ b/Documentation/accounting/delay-accounting.txt
@@ -54,9 +54,9 @@
 task of a thread group, the per-tgid statistics are also sent. More details
 are given in the taskstats interface description.
 
-The getdelays.c userspace utility in this directory allows simple commands to
-be run and the corresponding delay statistics to be displayed. It also serves
-as an example of using the taskstats interface.
+The getdelays.c userspace utility in tools/accounting directory allows simple
+commands to be run and the corresponding delay statistics to be displayed. It
+also serves as an example of using the taskstats interface.
 
 Usage
 -----