remoteproc: core: Prevent system suspend during remoteproc recovery

The system might go into suspend during recovery of any remoteproc.
This will interrupt the recovery process in between increasing the
recovery time. Make the platform device as wakeup capable and
use pm_stay_wake/pm_relax APIs to avoid system from going into
suspend during recovery.

Signed-off-by: Siddharth Gupta <sidgup@codeaurora.org>
Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/1588183482-21146-1-git-send-email-rishabhb@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>