soc: qcom: hwkm: fix minor issues

1. Fix key invalidate for double keys so that actual
   FBE keys can be removed when user is removed.
2. Don't use ICE slot for GP slot.
3. Handle KDF failures gracefully.

Change-Id: I161b96d36206378735ba564430e1f413065ba255
Signed-off-by: Gaurav Kashyap <gaurkash@codeaurora.org>