patches/telephony/baresip: fix init script and parallel build

The build sometimes fails with the error:

modules/ctrl_dbus/ctrl_dbus.c:69:10: fatal error: baresipbus.h: No such file or directory
   69 | #include "baresipbus.h"
      |          ^~~~~~~~~~~~~~

This should hopefully solve it.
Related pull request in OpenWrt:
- https://github.com/openwrt/telephony/pull/876/commits