ACPI / video: update the skip case for acpi_video_device_in_dod()

If the firmware has declared more than 8 video output devices, and the
one that control the internal panel's backlight is listed after the
first 8 output devices, the _DOD will not include it due to the current
i915 operation region implementation. As a result, we will not create a
backlight device for it while we should. Solve this problem by special
case the firmware that has 8+ output devices in that if we see such a
firmware, we do not test if the device is in _DOD list. The creation of
the backlight device will also enable the firmware to emit events on
backlight hotkey press when the acpi_osi= cmdline option is specified on
those affected ASUS laptops.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=70241
Reported-and-tested-by: Oleksij Rempel <linux@rempel-privat.de>
Reported-and-tested-by: Dmitry Tunin <hanipouspilot@gmail.com>
Reported-and-tested-by: Jimbo <jaime.91@hotmail.es>
Cc: 3.18+ <stable@vger.kernel.org> # 3.18+
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>