qcacmn: Reuse the tx descriptors in direct switch

Reuse the tx descriptors released in tx completions
without releasing the associated skbs to reduce
the cpu utilization in direct switch mode.

Change-Id: I4ab3ac58977a626344877b8a818a4dbc4864aaf3
CRs-Fixed: 3393968

dp/wifi3.0/dp_tx.h

@@ -410,11 +410,13 @@ qdf_nbuf_t dp_tx_exc_drop(struct cdp_soc_t *soc_hdl, uint8_t vdev_id,
 			  struct cdp_tx_exception_metadata *tx_exc_metadata);
 #endif
 #ifdef WLAN_SUPPORT_PPEDS
-void dp_ppeds_tx_desc_free(struct dp_soc *soc, struct dp_tx_desc_s *tx_desc);
+qdf_nbuf_t
+dp_ppeds_tx_desc_free(struct dp_soc *soc, struct dp_tx_desc_s *tx_desc);
 #else
-static inline
-void dp_ppeds_tx_desc_free(struct dp_soc *soc, struct dp_tx_desc_s *tx_desc)
+static inline qdf_nbuf_t
+dp_ppeds_tx_desc_free(struct dp_soc *soc, struct dp_tx_desc_s *tx_desc)
 {
+	return NULL;
 }
 #endif
 #ifndef QCA_HOST_MODE_WIFI_DISABLED