global: make 'char *path' const where possible

Signed-off-by: Christian Hesse <mail@eworm.de>
diff --git a/ui-refs.c b/ui-refs.c
index 2ec3858..456f610 100644
--- a/ui-refs.c
+++ b/ui-refs.c
@@ -136,7 +136,7 @@
 	return 0;
 }
 
-static void print_refs_link(char *path)
+static void print_refs_link(const char *path)
 {
 	html("<tr class='nohover'><td colspan='5'>");
 	cgit_refs_link("[...]", NULL, NULL, ctx.qry.head, NULL, path);