staging: vchiq: Export vchiq_get_service_userdata()

This is for service's callbacks to get their private data.
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20200629150945.10720-27-nsaenzjulienne@suse.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c

@@ -332,6 +332,7 @@ vchiq_get_service_userdata(unsigned int handle)
 	rcu_read_unlock();
 	return userdata;
 }
+EXPORT_SYMBOL(vchiq_get_service_userdata);
 
 static void
 mark_service_closing_internal(struct vchiq_service *service, int sh_thread)