docs: RCU: Convert torture.txt to ReST

- Add a SPDX header;
- Adjust document and section titles;
- Some whitespace fixes and new line breaks;
- Mark literal blocks as such;
- Add it to RCU/index.rst.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

Documentation/RCU/index.rst

@@ -18,6 +18,7 @@ RCU concepts
    whatisRCU
    rcu
    rculist_nulls
+   torture
    listRCU
    NMI-RCU
    UP

Documentation/locking/locktorture.rst

@@ -166,4 +166,4 @@ checked for such errors.  The "rmmod" command forces a "SUCCESS",
 two are self-explanatory, while the last indicates that while there
 were no locking failures, CPU-hotplug problems were detected.
 
-Also see: Documentation/RCU/torture.txt
+Also see: Documentation/RCU/torture.rst

MAINTAINERS

@@ -14437,7 +14437,7 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
 F:	Documentation/RCU/
 F:	include/linux/rcu*
 F:	kernel/rcu/
-X:	Documentation/RCU/torture.txt
+X:	Documentation/RCU/torture.rst
 X:	include/linux/srcu*.h
 X:	kernel/rcu/srcu*.c
 
@@ -17288,7 +17288,7 @@ M:	Josh Triplett <josh@joshtriplett.org>
 L:	linux-kernel@vger.kernel.org
 S:	Supported
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
-F:	Documentation/RCU/torture.txt
+F:	Documentation/RCU/torture.rst
 F:	kernel/locking/locktorture.c
 F:	kernel/rcu/rcuperf.c
 F:	kernel/rcu/rcutorture.c

kernel/rcu/rcutorture.c

@@ -7,7 +7,7 @@
  * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
  *	  Josh Triplett <josh@joshtriplett.org>
  *
- * See also:  Documentation/RCU/torture.txt
+ * See also:  Documentation/RCU/torture.rst
  */
 
 #define pr_fmt(fmt) fmt