libs/guest: Set console as disconnected on resume

There is currently an asymmetry between HVM where the page is cleared
and PV where the contents are restored.

Add xc_dom_console_set_disconnected() to only set the connection flag
for PV guests.

xenconsoled is responsible for setting the console connected when it
attaches.

Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Release-Acked-By: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>

tools/include/xenguest.h

@@ -337,6 +337,8 @@ int xc_dom_boot_image(struct xc_dom_image *dom);
 int xc_dom_compat_check(struct xc_dom_image *dom);
 int xc_dom_console_init(xc_interface *xch, uint32_t guest_domid,
                         xen_pfn_t console_gfn);
+int xc_dom_console_set_disconnected(xc_interface *xch, uint32_t guest_domid,
+                                    xen_pfn_t console_gfn);
 int xc_dom_gnttab_init(struct xc_dom_image *dom);
 int xc_dom_gnttab_seed(xc_interface *xch, uint32_t guest_domid,
                        bool is_hvm,