intel_menlow: fix memory leaks in error path

This patch includes below fixes in error path:
1. fix a memory leak if device_create_file failed in
intel_menlow_add_one_attribute
2. properly free added attributes before return error in
intel_menlow_register_sensor error handler
3. properly call acpi_bus_unregister_driver before return error in
intel_menlow_module_init

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>