x86: respect mapcache_domain_init() failing

The function itself properly handles and hands onwards failure from
create_perdomain_mapping(). Therefore its caller should respect possible
failure, too.

Fixes: 4b28bf6ae9 ("x86: re-introduce map_domain_page() et al")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>

xen/arch/x86/domain.c

@@ -858,7 +858,8 @@ int arch_domain_create(struct domain *d,
     }
     else if ( is_pv_domain(d) )
     {
-        mapcache_domain_init(d);
+        if ( (rc = mapcache_domain_init(d)) != 0 )
+            goto fail;
 
         if ( (rc = pv_domain_initialise(d)) != 0 )
             goto fail;