multiboot2-header: remove old clippy lint

multiboot2-header/src/information_request.rs

@@ -99,7 +99,6 @@ pub struct InformationRequestHeaderTagIter<'a> {
 
 impl<'a> InformationRequestHeaderTagIter<'a> {
     fn new(count: u32, base_ptr: *const MbiTagTypeId) -> Self {
-        #[allow(clippy::default_constructed_unit_structs)]
         Self {
             i: 0,
             count,