qcacmn: Printing Tx Desc in use count for DS mode

Requirement:
As part of serviceability for DS, display the number
of Tx descriptors currently in use by DS module
via “cfg80211tool athXX txrx_stats 260” like non-DS.

Snippet of log/code of Non-DS:
DP_PRINT_STATS("Tx Descriptors In Use = %u",
                       soc->stats.tx.desc_in_use);

Fix:
Introduced a new ops (dp_tx_ppe_ds_inuse_desc)
to display the current Tx desc in use.
dp_ppe_ds_inuse_desc API will be registered
to dp_tx_ppe_ds_inuse_desc in initialization
and it will be invoked from dp_print_soc_tx_stats API
to display the in_use desc via 260 command

Change-Id: I18971fc5d4cb5eb5437b012e3b89db7c9c2446b4
CRs-Fixed: 3352686

dp/wifi3.0/dp_internal.h

@@ -2552,6 +2552,14 @@ void dp_print_soc_tx_stats(struct dp_soc *soc);
  */
 void dp_print_soc_interrupt_stats(struct dp_soc *soc);
 
+/**
+ * dp_print_tx_ppeds_stats() - Print Tx in use stats for the soc in DS
+ * @soc: dp_soc handle
+ *
+ * Return: None
+ */
+
+void dp_print_tx_ppeds_stats(struct dp_soc *soc);
 #ifdef WLAN_DP_SRNG_USAGE_WM_TRACKING
 /**
  * dp_dump_srng_high_wm_stats() - Print the ring usage high watermark stats