gpio: smp2p: Update shadow variable before SMP2P edge OPEN

The client set values are ignored without notifying to client if the SMP2P
edge is not fully opened.

Update the client value in shadow variable and write back into SMEM once
the SMP2P edge is fully opened.

Change-Id: I9b5576397e0946d6a4311760ef0893743ad438a7
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>