platform/x86/intel/sdsi: Hide attributes if hardware doesn't support

platform/x86/intel/sdsi: Hide attributes if hardware doesn't support

Provisioning capabilities are enabled by a bit set by BIOS. Read this bit
and hide the provisioning attributes if the On Demand feature is not
enabled.

Also, remove the sdsi_enabled boolean from private and instead add a
features register since this will be used for future features.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20221119002343.1281885-3-david.e.box@linux.intel.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>