tracing: Convert local functions in tracing_map.c to static

Fix the following sparse warning:

kernel/trace/tracing_map.c:286:6: warning: symbol
'tracing_map_array_clear' was not declared. Should it be static?
kernel/trace/tracing_map.c:297:6: warning: symbol
'tracing_map_array_free' was not declared. Should it be static?
kernel/trace/tracing_map.c:319:26: warning: symbol
'tracing_map_array_alloc' was not declared. Should it be static?

Link: http://lkml.kernel.org/r/20200410073312.38855-1-yanaijie@huawei.comReported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/tracing_map.c

@@ -283,7 +283,7 @@ int tracing_map_add_key_field(struct tracing_map *map,
 	return idx;
 }
 
-void tracing_map_array_clear(struct tracing_map_array *a)
+static void tracing_map_array_clear(struct tracing_map_array *a)
 {
 	unsigned int i;
 
@@ -294,7 +294,7 @@ void tracing_map_array_clear(struct tracing_map_array *a)
 		memset(a->pages[i], 0, PAGE_SIZE);
 }
 
-void tracing_map_array_free(struct tracing_map_array *a)
+static void tracing_map_array_free(struct tracing_map_array *a)
 {
 	unsigned int i;
 
@@ -316,7 +316,7 @@ void tracing_map_array_free(struct tracing_map_array *a)
 	kfree(a);
 }
 
-struct tracing_map_array *tracing_map_array_alloc(unsigned int n_elts,
+static struct tracing_map_array *tracing_map_array_alloc(unsigned int n_elts,
 						  unsigned int entry_size)
 {
 	struct tracing_map_array *a;