tracing: #ifdef out uses of max trace when CONFIG_TRACER_MAX_TRACE is not set

tracing_max_lat_fops is used only when TRACER_MAX_TRACE enabled, so also
swith the related code. The related warning with defconfig under x86_64:

    CC      kernel/trace/trace.o
  kernel/trace/trace.c:5466:37: warning: ‘tracing_max_lat_fops’ defined but not used [-Wunused-const-variable]
   static const struct file_operations tracing_max_lat_fops = {
Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace.c

@@ -4548,6 +4548,8 @@ tracing_thresh_write(struct file *filp, const char __user *ubuf,
 	return ret;
 }
 
+#ifdef CONFIG_TRACER_MAX_TRACE
+
 static ssize_t
 tracing_max_lat_read(struct file *filp, char __user *ubuf,
 		     size_t cnt, loff_t *ppos)
@@ -4562,6 +4564,8 @@ tracing_max_lat_write(struct file *filp, const char __user *ubuf,
 	return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);
 }
 
+#endif
+
 static int tracing_open_pipe(struct inode *inode, struct file *filp)
 {
 	struct trace_array *tr = inode->i_private;
@@ -5463,12 +5467,14 @@ static const struct file_operations tracing_thresh_fops = {
 	.llseek		= generic_file_llseek,
 };
 
+#ifdef CONFIG_TRACER_MAX_TRACE
 static const struct file_operations tracing_max_lat_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_max_lat_read,
 	.write		= tracing_max_lat_write,
 	.llseek		= generic_file_llseek,
 };
+#endif
 
 static const struct file_operations set_tracer_fops = {
 	.open		= tracing_open_generic,