ACPI / video: Dummy acpi_video_register should return error code

The inline acpi_video_register stub simply allows compilation on systems
with CONFIG_ACPI_VIDEO disabled. the dummy acpi_video_register does not
register an acpi_bus_driver at all. The inline acpi_video_register should
return to indicate lack of support when attempting to register an
acpi_bus_driver on such a system with CONFIG_ACPI_VIDEO disabled.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Reviewed-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>