qcacld-3.0: Correctly export hdd_conn_set_connection_state()

There are multiple issues with how hdd_conn_set_connection_state()
is exported:
1) The prototype is defined in wlan_hdd_cfg80211.h even though the
   implementation is in wlan_hdd_assoc.c.
2) The prototype uses the "extern" keyword which violates the Linux
   Kernel coding style.
3) The implementation is documented instead of the interface.

To address these issues move the prototype (without "extern") as well
as the documentation to wlan_hdd_assoc.h.

Change-Id: Ie2b80e953cc500c10ae14d94c375cc1487241b6c
CRs-Fixed: 2357078

core/hdd/inc/wlan_hdd_assoc.h

@@ -233,6 +233,18 @@ bool hdd_is_connecting(struct hdd_station_ctx *hdd_sta_ctx);
  */
 bool hdd_is_fils_connection(struct hdd_adapter *adapter);
 
+/**
+ * hdd_conn_set_connection_state() - set connection state
+ * @adapter: pointer to the adapter
+ * @conn_state: connection state
+ *
+ * This function updates the global HDD station context connection state.
+ *
+ * Return: none
+ */
+void hdd_conn_set_connection_state(struct hdd_adapter *adapter,
+				   eConnectionState conn_state);
+
 /**
  * hdd_conn_is_connected() - Function to check connection status
  * @sta_ctx:    pointer to global HDD Station context

core/hdd/src/wlan_hdd_assoc.c

@@ -241,15 +241,6 @@ hdd_conn_set_authenticated(struct hdd_adapter *adapter, uint8_t auth_state)
 
 }
 
-/**
- * hdd_conn_set_connection_state() - set connection state
- * @adapter: pointer to the adapter
- * @conn_state: connection state
- *
- * This function updates the global HDD station context connection state.
- *
- * Return: none
- */
 void hdd_conn_set_connection_state(struct hdd_adapter *adapter,
 				   eConnectionState conn_state)
 {

core/hdd/src/wlan_hdd_cfg80211.h

@@ -296,8 +296,6 @@ void wlan_hdd_cfg80211_deregister_frames(struct hdd_adapter *adapter);
 void hdd_reg_notifier(struct wiphy *wiphy,
 				 struct regulatory_request *request);
 
-extern void hdd_conn_set_connection_state(struct hdd_adapter *adapter,
-					  eConnectionState connState);
 QDF_STATUS wlan_hdd_validate_operation_channel(struct hdd_adapter *adapter,
 					       int channel);
 #ifdef FEATURE_WLAN_TDLS