msm: 8960: Cleanup of memory held for frames sent over SMD transport

In case of SMD (Shared memory driver) as HCI transport; once the
Tx packets are written over SMD channel, the corresponding memory
objects were not cleaned resulting in memory leaking.
Now these are appropriately cleaned up to avoid reset because of low
memory in long run scenarios.

Change-Id: Id53a79fb1c6b6a6cf756fd760a84fca8585c4a68
CRs-fixed: 306045
Signed-off-by: AnubhavGupta <anubhavg@codeaurora.org>