ACPI: video: use ACPI backlight for HP 635 Notebook

The default backlight interface is AMD's radeon_bl0 which does not
work on this system, so use the ACPI backlight interface on it
instead.

BugLink: https://bugs.launchpad.net/bugs/1894667


Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Alex Hung <alex.hung@canonical.com>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>