remoteproc: qcom: q6v5: Add common panic handler

remoteproc: qcom: q6v5: Add common panic handler

Add a common panic handler that invokes a stop request and sleep enough
to let the remoteproc flush it's caches etc in order to aid post mortem
debugging. For now a hard coded 200ms is returned to the remoteproc
core, this value is taken from the downstream kernel.

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200324052904.738594-4-bjorn.andersson@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>