ACPI: bay: use IS_ERR for return of register_platform_device_simple

register_platform_device_simple returns ERR_PTR(foo), so test it with
IS_ERR(foo).

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>