x86/mm: Fix enc_status_change_finish_noop()

enc_status_change_finish_noop() is now defined as always-fail, which
doesn't make sense for noop.

The change has no user-visible effect because it is only called if the
platform has CC_ATTR_MEM_ENCRYPT. All platforms with the attribute
override the callback with their own implementation.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: https://lore.kernel.org/all/20230606095622.1939-4-kirill.shutemov%40linux.intel.com