tracing: Have __dynamic_array() define a field

This is part of a patch set that removes the show_format method
in the ftrace event macros.

This patch set requires that all fields are added to the
ftrace_event_call->fields. This patch changes __dynamic_array()
to call trace_define_field() to include fields that use __dynamic_array().
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B273D36.8090100@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace_export.c

@@ -175,7 +175,12 @@ ftrace_format_##name(struct ftrace_event_call *unused,			\
 		return ret;
 
 #undef __dynamic_array
-#define __dynamic_array(type, item)
+#define __dynamic_array(type, item)					\
+	ret = trace_define_field(event_call, #type, #item,		\
+				 offsetof(typeof(field), item),		\
+				 0, is_signed_type(type), FILTER_OTHER);\
+	if (ret)							\
+		return ret;
 
 #undef FTRACE_ENTRY
 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print)		\