qcacmn: Add cdp api for dp tx desc availability

Add cdp api to check if tx desc pool available descriptor
threshold has reached.

Change-Id: Ie542d03dd865d32aa6e01da00328aa51728b4276
CRs-Fixed: 2369218
diff --git a/dp/wifi3.0/dp_main.c b/dp/wifi3.0/dp_main.c
index a42cd2e..9c06974 100644
--- a/dp/wifi3.0/dp_main.c
+++ b/dp/wifi3.0/dp_main.c
@@ -9166,6 +9166,7 @@
 	.flow_pool_unmap_handler = dp_tx_flow_pool_unmap,
 	.register_pause_cb = dp_txrx_register_pause_cb,
 	.dump_flow_pool_info = dp_tx_dump_flow_pool_info,
+	.tx_desc_thresh_reached = dp_tx_desc_thresh_reached,
 #endif /* QCA_LL_TX_FLOW_CONTROL_V2 */
 };