msm: ADSPRPC: Handle glink close properly

Use refcount flag to check for glink channel close. Set refcount in
glink channel open, consider glink channel close if the refcount is set.

Change-Id: Ie0d6c87f030a991a8a6da051ed5c5e9660dbe9a8
Signed-off-by: Tharun Kumar Merugu <mtharu@codeaurora.org>