qcacmn: Fix null pointer issue in LPM case

In the LPM case, if the tx desc has been force
freed in the dp_bus_suspend ->dp_find_missing_tx_comp,
then after data transfer resumed, fw may report
tx complete for the same tx desc, and we should
skip it to avoid null pointer access.
The reason why set default vdev_id to 0xff is:
Since in this case, it happned disconnect before
suspend, so the tx desc pool will be deleted and
reinitalized when resume, so the pdev is null in
the force freed tx_desc and vdev_id should be changed
from 0 to DP_INVALID_VDEV_ID, otherwise the below logic
in the tx complete handler will not skip handling
this freed tx_desc.

if (qdf_unlikely((tx_desc->vdev_id == DP_INVALID_VDEV_ID) &&
    !tx_desc->flags)) {
	DP_STATS_INC(soc, tx.tx_comp_exception,1);
	dp_tx_desc_check_corruption(tx_desc);
	continue;
}

Change-Id: I5f3ff6fd783893f92a0fd6b3db7457b280fcb1c8
CRs-Fixed: 3447465

dp/wifi3.0/li/dp_li_tx.c

@@ -582,6 +582,7 @@ QDF_STATUS dp_tx_desc_pool_init_li(struct dp_soc *soc,
 
 		tx_desc->id = id;
 		tx_desc->pool_id = pool_id;
+		tx_desc->vdev_id = DP_INVALID_VDEV_ID;
 		dp_tx_desc_set_magic(tx_desc, DP_TX_MAGIC_PATTERN_FREE);
 		tx_desc = tx_desc->next;
 		count++;