tracing: Split tracing initialization into two for early initialization

Create an early_trace_init() function that will initialize the buffers and
allow for ealier use of trace_printk(). This will also allow for future work
to have function tracing start earlier at boot up.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/trace.c

@@ -7999,7 +7999,7 @@ out:
 	return ret;
 }
 
-void __init trace_init(void)
+void __init early_trace_init(void)
 {
 	if (tracepoint_printk) {
 		tracepoint_print_iter =
@@ -8010,6 +8010,10 @@ void __init trace_init(void)
 			static_key_enable(&tracepoint_printk_key.key);
 	}
 	tracer_alloc_buffers();
+}
+
+void __init trace_init(void)
+{
 	trace_event_init();
 }