soc: qcom: subsystem_notif: Fix suspicious indent

This is indented oddly, and doesn't need the local ret variable.
Clean things up and also drop the cast from void because that
isn't necessary and we're here.

Change-Id: I02106107ea6e7500db6cc822a2d5cf88c5d0aa38
Cc: Puja Gupta <pujag@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>