tracing/events: add export symbols for trace events in modules

Impact: let modules add trace events

The trace event code requires some functions to be exported to allow
modules to use TRACE_EVENT. This patch adds EXPORT_SYMBOL_GPL to the
necessary functions.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 0e70fb0..83a8abb 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -94,6 +94,7 @@
 
 	return len;
 }
+EXPORT_SYMBOL_GPL(trace_seq_printf);
 
 int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
 {
@@ -538,6 +539,7 @@
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(register_ftrace_event);
 
 /**
  * unregister_ftrace_event - remove a no longer used event
@@ -551,6 +553,7 @@
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(unregister_ftrace_event);
 
 /*
  * Standard events