soc: qcom: glink_smd_xprt: Ensure faked open ack occurs in legacy cases

When the transport is assuming the remote side of the channel is legacy,
the transport waits until the channel has been opened before faking the
open ack back to the core.  This can stall the channel migration process
if the channel never gets opened.

Move the faked open ack to the end of the open command processing so that
the core always gets the faked ack regardless of the channel open state.

Change-Id: Iba65215fbb762d57ac16634347b98e2e312e2470
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>