ACPI: video: Drop X86 dependency from Kconfig

The ACPI video device is also present in ARM64 laptops, so drop the
Kconfig dependency on X86 for ACPI_VIDEO.

Signed-off-by: Riwen Lu <luriwen@kylinos.cn>
[ rjw: Subject rewrite, changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>