tracing: Rename (un)register_ftrace_event() to (un)register_trace_event()

The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The functions (un)register_ftrace_event() is
really about trace_events, and the name should be register_trace_event()
instead.

Also renamed ftrace_event_reg() to trace_event_reg() for the same reason.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 483cecf..4ba2b8e 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1450,14 +1450,14 @@
 
 static int __init init_blk_tracer(void)
 {
-	if (!register_ftrace_event(&trace_blk_event)) {
+	if (!register_trace_event(&trace_blk_event)) {
 		pr_warning("Warning: could not register block events\n");
 		return 1;
 	}
 
 	if (register_tracer(&blk_tracer) != 0) {
 		pr_warning("Warning: could not register the block tracer\n");
-		unregister_ftrace_event(&trace_blk_event);
+		unregister_trace_event(&trace_blk_event);
 		return 1;
 	}