ACPI: scan: Drop outdated comment regarding removed function

ACPI: scan: Drop outdated comment regarding removed function

The function acpi_video_get_capabilities() was removed from
drivers/acpi/video_detect.c by commit 87521e16a7ab ("acpi-video-detect:
Rewrite backlight interface selection logic") in 2015.  At the time,
comments about this function were just removed, and no replacement
seemed to be proposed.

Drop the reference to acpi_video_get_capabilities() here as well.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
[ rjw: Subject adjustment, changelog edits ]
Link: https://patch.msgid.link/20251230160644.100439-1-Julia.Lawall@inria.fr
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>