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>

kernel/trace/trace_branch.c

@@ -244,7 +244,7 @@ static int annotated_branch_stat_headers(struct seq_file *m)
 	return 0;
 }
 
-static inline long get_incorrect_percent(struct ftrace_branch_data *p)
+static inline long get_incorrect_percent(const struct ftrace_branch_data *p)
 {
 	long percent;
 
@@ -332,10 +332,10 @@ annotated_branch_stat_next(void *v, int idx)
 	return p;
 }
 
-static int annotated_branch_stat_cmp(void *p1, void *p2)
+static int annotated_branch_stat_cmp(const void *p1, const void *p2)
 {
-	struct ftrace_branch_data *a = p1;
-	struct ftrace_branch_data *b = p2;
+	const struct ftrace_branch_data *a = p1;
+	const struct ftrace_branch_data *b = p2;
 
 	long percent_a, percent_b;