spcom: fix server rx-abort after SP reset and channel closed

Upon SP reset, the Glink driver notifies about ch remote disconnect,
and then about link down.
The server rx-abort handling happens after the channel is closed.

Change-Id: I68a4d00c84f55e954bfb0f678483e5f245cc316d
Signed-off-by: Amir Samuelov <amirs@codeaurora.org>