libxl: except Dom0 from setting PoD target

Dom0 is never started in PoD mode, and hence it can at "best" do harm if
we try to set a PoD target for it.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>

tools/libs/light/libxl_mem.c

@@ -306,7 +306,7 @@ retry_transaction:
         }
     }
 
-    if (d_config.c_info.type != LIBXL_DOMAIN_TYPE_PV) {
+    if (domid && d_config.c_info.type != LIBXL_DOMAIN_TYPE_PV) {
         r = xc_domain_set_pod_target(ctx->xch, domid,
                 (new_target_memkb + size) / 4, NULL, NULL, NULL);
         if (r != 0) {