x86: cpu -- Report when unsupported compact xsave frame detected

We don't have yet support of compacted xsave frames so report
error on cpu-check, checkpoint, restore actions. Basically
it is done in cpu_init routine which is called in the sites
we're interested in.

Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>