ACPI / video: Make logic a little easier to understand.

Make code paths a little easier to follow, and don't needlessly continue
list iteration.

Signed-off-by: Danny Baumann <dannybaumann@web.de>
Reviewed-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>