qcacld-3.0: Remove struct hdd_tgt_cfg forward reference

Change I84e9ac5ccfe8faaa00dfc448defb81fb792263d5 ("qcacld-3.0: Add
support for NDP vendor commands and NDI Create") introduced a forward
reference to struct hdd_tgt_cfg. That struct doesn't actually exist,
so remove the forward reference.

Change-Id: Ic3129f6c0c8e55824ba066d5d36a7d10868f9f50
CRs-Fixed: 2368720

core/hdd/src/wlan_hdd_nan_datapath.h

@@ -25,7 +25,6 @@
 #define __WLAN_HDD_NAN_DATAPATH_H
 
 struct hdd_context;
-struct hdd_tgt_cfg;
 struct hdd_config;
 struct hdd_adapter;
 struct wireless_dev;