remoteproc: qcom: Introduce sysmon

The sysmon client communicates either via a dedicated SMD/GLINK channel
or via QMI encoded messages over IPCROUTER with remote processors in
order to perform graceful shutdown and inform about other remote
processors shutting down.

Acked-By: Chris Lew <clew@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>