soc: qcom: glink_smd_xprt: Generate close ack signal in all cases

If the transport is simulating the local side of the channel as legacy SMD
and the underlying SMD channel is not opened, the close ack signal will
not be generated, leading to a resource leak in the core.

Ensure the close ack signal is generated in this scenario.

Change-Id: I3ff30be47019e01cd609f34204f071e09c0b8918
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>