tools/virtio: add struct module forward declaration

Declarate struct module in our linux/module.h stub.

Created using Cursor CLI.

Message-ID: <[e-mail]>
Acked-by: Jason Wang <[e-mail]>
Signed-off-by: Michael S. Tsirkin <[e-mail]>

tools/virtio/linux/module.h

···
 /* SPDX-License-Identifier: GPL-2.0 */
 #include <linux/export.h>
 
+struct module;
+
 #define MODULE_LICENSE(__MODULE_LICENSE_value) \
 	static __attribute__((unused)) const char *__MODULE_LICENSE_name = \
 		__MODULE_LICENSE_value