perf callchain: Make display use of branch_type_stat const

Display code doesn't modify the branch_type_stat so switch uses to
const. This is done to aid refactoring struct callchain_list where
current the branch_type_stat is embedded even if not used.

Signed-off-by: Ian Rogers <[e-mail]>
Cc: K Prateek Nayak <[e-mail]>
Cc: Ravi Bangoria <[e-mail]>
Cc: Sandipan Das <[e-mail]>
Cc: Anshuman Khandual <[e-mail]>
Cc: German Gomez <[e-mail]>
Cc: James Clark <[e-mail]>
Cc: Nick Terrell <[e-mail]>
Cc: Sean Christopherson <[e-mail]>
Cc: Changbin Du <[e-mail]>
Cc: liuwenyu <[e-mail]>
Cc: Yang Jihong <[e-mail]>
Cc: Masami Hiramatsu <[e-mail]>
Cc: Miguel Ojeda <[e-mail]>
Cc: Song Liu <[e-mail]>
Cc: Leo Yan <[e-mail]>
Cc: Kajol Jain <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Athira Rajeev <[e-mail]>
Cc: Yanteng Si <[e-mail]>
Cc: Liam Howlett <[e-mail]>
Cc: Paolo Bonzini <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Namhyung Kim <[e-mail]>

tools/perf/util/branch.c

···
 	return branch_type_name(e->flags.type);
 }
 
-void branch_type_stat_display(FILE *fp, struct branch_type_stat *st)
+void branch_type_stat_display(FILE *fp, const struct branch_type_stat *st)
 {
 	u64 total = 0;
 	int i;
···
 	return scnprintf(bf, size, "%s%s", (idx) ? " " : " (", str);
 }
 
-int branch_type_str(struct branch_type_stat *st, char *bf, int size)
+int branch_type_str(const struct branch_type_stat *st, char *bf, int size)
 {
 	int i, j = 0, printed = 0;
 	u64 total = 0;

tools/perf/util/branch.h

···
 const char *branch_type_name(int type);
 const char *branch_new_type_name(int new_type);
 const char *get_branch_type(struct branch_entry *e);
-void branch_type_stat_display(FILE *fp, struct branch_type_stat *st);
-int branch_type_str(struct branch_type_stat *st, char *bf, int bfsize);
+void branch_type_stat_display(FILE *fp, const struct branch_type_stat *st);
+int branch_type_str(const struct branch_type_stat *st, char *bf, int bfsize);
 
 const char *branch_spec_desc(int spec);
 

tools/perf/util/callchain.c

···
 static int branch_to_str(char *bf, int bfsize,
 			 u64 branch_count, u64 predicted_count,
 			 u64 abort_count,
-			 struct branch_type_stat *brtype_stat)
+			 const struct branch_type_stat *brtype_stat)
 {
 	int printed, i = 0;
 
···
 			     u64 abort_count, u64 cycles_count,
 			     u64 iter_count, u64 iter_cycles,
 			     u64 from_count,
-			     struct branch_type_stat *brtype_stat)
+			     const struct branch_type_stat *brtype_stat)
 {
 	int printed;
 
···
 				   u64 abort_count, u64 cycles_count,
 				   u64 iter_count, u64 iter_cycles,
 				   u64 from_count,
-				   struct branch_type_stat *brtype_stat)
+				   const struct branch_type_stat *brtype_stat)
 {
 	char str[256];