ACPI / video: Propagate the error code for acpi_video_register

Report the actual error code from acpi_bus_register_driver(), it may
help future debugging (typically ENODEV as previously reported, but the
unusual cases are where it may help most).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>