tracing: Change "char *" string form to "char []"

The "char []" string form declares a single variable. It is better
than "char *" which creates two variables in the final assembly.

Link: https://lkml.kernel.org/r/20220512143230.28796-1-liqiong@nfschina.com

Signed-off-by: liqiong <liqiong@nfschina.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Author: liqiong

kernel/trace/trace.c

@@ -4252,7 +4252,7 @@ static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file
 				       unsigned int flags)
 {
 	bool tgid = flags & TRACE_ITER_RECORD_TGID;
-	const char *space = "            ";
+	static const char space[] = "            ";
 	int prec = tgid ? 12 : 2;
 
 	print_event_info(buf, m);

kernel/trace/trace_events_hist.c

@@ -4165,7 +4165,7 @@ static int create_val_field(struct hist_trigger_data *hist_data,
 	return __create_val_field(hist_data, val_idx, file, NULL, field_str, 0);
 }
 
-static const char *no_comm = "(no comm)";
+static const char no_comm[] = "(no comm)";
 
 static u64 hist_field_execname(struct hist_field *hist_field,
 			       struct tracing_map_elt *elt,