canbus: Call can_notify_rx() at startup so low-level code does not need to

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/generic/canbus.c

@@ -213,6 +213,7 @@ void
 canbus_set_uuid(void *uuid)
 {
     memcpy(canbus_uuid, uuid, sizeof(canbus_uuid));
+    canbus_notify_rx();
 
     // Send initial message
     can_process_uuid(0, 0, NULL);