Some apple laptop models have an ACPI device with a HID of APP000B
and that device has an IO resource (so it does not describe the new
unsupported MMIO based gmux type), but there actually is no gmux
in the laptop at all.

The gmux_probe() function of the actual apple-gmux driver has code
to detect this, this code has been factored out into a new
apple_gmux_detect() helper in apple-gmux.h.

Use this new function to fix acpi_video_get_backlight_type() wrongly
returning apple_gmux as type on the following laptops:

MacBookPro5,4
https://pastebin.com/8Xjq7RhS

MacBookPro8,1
https://linux-hardware.org/?probe=e513cfbadb&log=dmesg

MacBookPro9,2
https://bugzilla.kernel.org/attachment.cgi?id=278961

MacBookPro10,2
https://lkml.org/lkml/2014/9/22/657

MacBookPro11,2
https://forums.fedora-fr.org/viewtopic.php?id=70142

MacBookPro11,4
https://raw.githubusercontent.com/im-0/investigate-card-reader-suspend-problem-on-mbp11.4/mast

Fixes: 21245df3 ("ACPI: video: Add Apple GMUX brightness control detection")
Link: https://lore.kernel.org/platform-driver-x86/20230123113750.462144-1-hdegoede@redhat.com/Reported-by: Emmanouil Kouroupakis <kartebi@gmail.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230124105754.62167-4-hdegoede@redhat.com