qcacmn: Fix TX stastics failed to take TSO segment into account

Currently, we record TX musdu number and packet length, which falls into
three categories: from stack, from host and successfully transmitted. In
TSO mode, the msdu from stack will be divided into several fragments and
each of the fragment will be transmitted as an individual msdu. This change
will take TSO into account when it comes to the 3 forms of TX statstics.

Change-Id: Ie11cb7541b4e109609bf3104739a5e19f51dcc13
CRs-Fixed: 3361412

dp/wifi3.0/dp_tx.h

@@ -1320,4 +1320,25 @@ dp_tx_outstanding_dec(struct dp_pdev *pdev)
 	dp_update_tx_desc_stats(pdev);
 }
 #endif //QCA_TX_LIMIT_CHECK
+/**
+ * dp_tx_get_pkt_len() - Get the packet length of a msdu
+ * @tx_desc: tx descriptor
+ *
+ * Return: Packet length of a msdu. If the packet is fragmented,
+ * it will return the single fragment length.
+ *
+ * In TSO mode, the msdu from stack will be fragmented into small
+ * fragments and each of these new fragments will be transmitted
+ * as an individual msdu.
+ *
+ * Please note that the length of a msdu from stack may be smaller
+ * than the length of the total length of the fragments it has been
+ * fragmentted because each of the fragments has a nbuf header.
+ */
+static inline uint32_t dp_tx_get_pkt_len(struct dp_tx_desc_s *tx_desc)
+{
+	return tx_desc->frm_type == dp_tx_frm_tso ?
+		tx_desc->msdu_ext_desc->tso_desc->seg.total_len :
+		qdf_nbuf_len(tx_desc->nbuf);
+}
 #endif