tracing: Use generic type for comparator function

Comparator function type, cmp_func_t, is defined in the types.h,
use it in the code.

Link: http://lkml.kernel.org/r/20191007135656.37734-3-andriy.shevchenko@linux.intel.com

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_stat.h b/kernel/trace/trace_stat.h
index 8786d17..31d7dc5 100644
--- a/kernel/trace/trace_stat.h
+++ b/kernel/trace/trace_stat.h
@@ -16,7 +16,7 @@ struct tracer_stat {
 	void			*(*stat_start)(struct tracer_stat *trace);
 	void			*(*stat_next)(void *prev, int idx);
 	/* Compare two entries for stats sorting */
-	int			(*stat_cmp)(void *p1, void *p2);
+	cmp_func_t		stat_cmp;
 	/* Print a stat entry */
 	int			(*stat_show)(struct seq_file *s, void *p);
 	/* Release an entry */