Remove () returned value

Author: GuillaumeGomez

compiler/rustc_codegen_gcc/src/builder.rs

@@ -1608,7 +1608,7 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
         (value1, value2)
     }
 
-    fn filter_landing_pad(&mut self, pers_fn: Function<'gcc>) -> () {
+    fn filter_landing_pad(&mut self, pers_fn: Function<'gcc>) {
         // TODO(antoyo): generate the correct landing pad
         self.cleanup_landing_pad(pers_fn);
     }