qcacmn: Save first msdu and last msdu flags in NULL queue handler

We need to save the first msdu and last msdu flags in nbuf cb
so we can do WDS source port learning only for the first msdu
even in the null_q_handler. Without this fix we observed traffic
stops when WMM is disabled.

Change-Id: Ic7870354519ebebb8a5025b3e6c9741064686199

dp/wifi3.0/dp_rx_err.c

@@ -351,6 +351,11 @@ dp_rx_null_q_desc_handle(struct dp_soc *soc, struct dp_rx_desc *rx_desc,
 
 	pool_id = rx_desc->pool_id;
 
+	qdf_nbuf_set_rx_chfrag_start(nbuf,
+			hal_rx_msdu_end_first_msdu_get(rx_desc->rx_buf_start));
+	qdf_nbuf_set_rx_chfrag_end(nbuf,
+			hal_rx_msdu_end_last_msdu_get(rx_desc->rx_buf_start));
+
 	l2_hdr_offset =
 		hal_rx_msdu_end_l3_hdr_padding_get(rx_desc->rx_buf_start);