In `drivers/rptun/rptun.c`, we have a `rptun_is_recursive` function,
which lets rptun thread run recursively. Then the `usrsock_rpmsg_ept_cb`
may be called inside `usrsock_rpmsg_ept_cb`, which can cause some
unexpected behavior, so we add a queue to keep the order of incoming
messages to reduce the complexity.
Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
90a8e2e422