Fix violations of Flake8 Bugbear B037

__init__() methods should not return anything.

loopy/target/execution.py

@@ -777,7 +777,6 @@ def __init__(self, t_unit: TranslationUnit, entrypoint: str):
             self.packing_controller = SeparateArrayPackingController(self.sep_info)
         else:
             self.packing_controller = None
-            return None
 
     def check_for_required_array_arguments(self, input_args):
         # Formerly, the first exception raised when a required argument is not