soc: qcom: glink_smd_xprt: move SMD close to close ACK

Even though the CLOSE command is sent over the control channel before an
SMD channel is closed, the events may be processed out of order on the
receiving system causing an invalid state transfer.

Move the SMD channel close to the Close ACK to ensure serialization of
the CLOSE command and the SMD channel close event.

Change-Id: Id68ea2fffb7bf744bbbba290c912f47d6edb869c
Signed-off-by: Eric Holmberg <eholmber@codeaurora.org>