soc: qcom: service-notifier: Add EARLY_PD_DOWN to PD states

Add the EARLY_PD_DOWN state to the set of possible states
for a PD. The PD will enter this state and send an indication
to the HLOS shortly before sending the PD_DOWN indication. This
indication does not require an ACK back, unlike the PD_[UP/DOWN]
indication.

This indication is sent when PD dumps are collected, and
before a PD dies. Any memory that is part of the PD dumps
should not be unmapped as part of the handling for this
indication, as it may be used during the PD dump collection.

Change-Id: I8797510e86e41ceb64c4afff55d7c286f385b98d
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>