soc: qcom: glink: Fix race condition between tx and close operation

The channel is closed locally by the client either as part of SSR or normal
working scenario. The transmit operation does not check the transport or
channel states before queuing the packet for transmit operation. This
causes the transmit operation to access stale transport or channel context.

Check the transport and channel state before queuing the packet for
transmission.

CRs-Fixed: 947627
Change-Id: Ic6f8350b6b5e51b641794255f8520ff4616343bb
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>