lib/plist.c: make CONFIG_DEBUG_PI_LIST selectable

Change CONFIG_DEBUG_PI_LIST to be user-selectable, and add a title and
description.  Remove the dependency on DEBUG_RT_MUTEXES since they were
changed to use rbtrees, and there are other users of plists now.

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/Kconfig.debug

@@ -833,11 +833,6 @@ config DEBUG_RT_MUTEXES
 	 This allows rt mutex semantics violations and rt mutex related
 	 deadlocks (lockups) to be detected and reported automatically.
 
-config DEBUG_PI_LIST
-	bool
-	default y
-	depends on DEBUG_RT_MUTEXES
-
 config RT_MUTEX_TESTER
 	bool "Built-in scriptable tester for rt-mutexes"
 	depends on DEBUG_KERNEL && RT_MUTEXES
@@ -1063,6 +1058,16 @@ config DEBUG_LIST
 
 	  If unsure, say N.
 
+config DEBUG_PI_LIST
+	bool "Debug priority linked list manipulation"
+	depends on DEBUG_KERNEL
+	help
+	  Enable this to turn on extended checks in the priority-ordered
+	  linked-list (plist) walking routines.  This checks the entire
+	  list multiple times during each manipulation.
+
+	  If unsure, say N.
+
 config DEBUG_SG
 	bool "Debug SG table operations"
 	depends on DEBUG_KERNEL