Allow the wcnss smd edge to be described as a child of the wcnss
remoteproc node and make the edge life cycle follow the running state of
the remoteproc.

This bond is necessary to clean up the smd state when the remote
processor is suddenly removed, and in some cases even when it shut down
in a controlled fasion.
Signed-off-by: NBjorn Andersson <bjorn.andersson@linaro.org>