board: xen: De-initialize before jumping to Linux

Free resources used by Xen board before jumping to Linux kernel.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Anastasiia Lukianenko <anastasiia_lukianenko@epam.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/xen/hypervisor.c

@@ -242,3 +242,11 @@ void xen_init(void)
 	init_gnttab();
 }
 
+void xen_fini(void)
+{
+	debug("%s\n", __func__);
+
+	fini_gnttab();
+	fini_xenbus();
+	fini_events();
+}