ftrace: only have ftrace_kill atomic

When an anomaly is detected, we need a way to completely disable
ftrace. Right now we have two functions: ftrace_kill and ftrace_kill_atomic.
The ftrace_kill tries to do it in a "nice" way by converting everything
back to a nop.

The "nice" way is dangerous itself, so this patch removes it and only
has the "atomic" version, which is all that is needed.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 79fa10c..ac58e94 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -40,7 +40,7 @@
 # define register_ftrace_function(ops) do { } while (0)
 # define unregister_ftrace_function(ops) do { } while (0)
 # define clear_ftrace_function(ops) do { } while (0)
-static inline void ftrace_kill_atomic(void) { }
+static inline void ftrace_kill(void) { }
 #endif /* CONFIG_FUNCTION_TRACER */
 
 #ifdef CONFIG_DYNAMIC_FTRACE
@@ -117,7 +117,6 @@
 
 /* totally disable ftrace - can not re-enable after this */
 void ftrace_kill(void);
-void ftrace_kill_atomic(void);
 
 static inline void tracer_disable(void)
 {