qcacmn: Add support to enable tx hw latency stats at run time

This feature can be enabled runtime using sysfs interface.
Support is added to dump and clear the histogram stats.

The lower delay regions has to be more granular to indicate any
medium related issues for time sensitive XR applications.

Change-Id: I0a44a54d12d92ce016de349810cb2bedebaf9a58
CRs-Fixed: 2981006

dp/inc/cdp_txrx_cmn_struct.h

@@ -92,6 +92,7 @@
 #define CDP_DISCONNECT_STATS       25
 #define CDP_DP_RX_FISA_STATS	   26
 #define CDP_DP_SWLM_STATS	   27
+#define CDP_DP_TX_HW_LATENCY_STATS 28
 
 #define WME_AC_TO_TID(_ac) (       \
 		((_ac) == WME_AC_VO) ? 6 : \