qcacmn: Add wbm head/tail pointer stats to dp_txrx_stats

Add wbm head/tail pointer stats to dp_txrx_stats and ring
usage percentage for all SRC and DST rings.
Stats added to the following cmd: iwpriv wlan0 txrx_stats 26 0

CRs-Fixed: 2865996
Change-Id: I7d144d87c5f3485ec9ba85f50b036b69a64e53c6

dp/wifi3.0/dp_main.c

@@ -8375,6 +8375,8 @@ char *dp_srng_get_str_from_hal_ring_type(enum hal_ring_type ring_type)
 		return "Rxdma_monitor_desc";
 	case RXDMA_MONITOR_STATUS:
 		return "Rxdma_monitor_status";
+	case WBM_IDLE_LINK:
+		return "WBM_hw_idle_link";
 	default:
 		dp_err("Invalid ring type");
 		break;