Remove unnecessary default argument from initialize_block_iterator

I noticed that initialize_block_iterator has a default value for one
of its arguments, but this is not needed as this function has a single
caller that always passes all arguments.  This patch removes the
default.  Tested by rebuilding.


diff --git a/gdb/block.c b/gdb/block.c
index 8e37a63..acf21e2 100644
--- a/gdb/block.c
+++ b/gdb/block.c
@@ -438,7 +438,7 @@ get_block_compunit_symtab (const struct block *block)
 static void
 initialize_block_iterator (const struct block *block,
 			   struct block_iterator *iter,
-			   const lookup_name_info *name = nullptr)
+			   const lookup_name_info *name)
 {
   enum block_enum which;
   struct compunit_symtab *cu;