net/: Fix some incorrect comments that go back for years (but have also been cloned in newer files). The network was once interrupt driver, but now runs on the work queue with a semaphore to enforce mutual exclusion.

net/bluetooth/bluetooth_callback.c

@@ -63,7 +63,7 @@
  *   OK if packet has been processed, otherwise ERROR.
  *
  * Assumptions:
- *   This function is called at the interrupt level with interrupts disabled.
+ *   This function is called at the with the network disabled.
  *
  ****************************************************************************/
 

net/bluetooth/bluetooth_conn.c

@@ -128,9 +128,7 @@ FAR struct bluetooth_conn_s *bluetooth_conn_alloc(void)
 {
   FAR struct bluetooth_conn_s *conn;
 
-  /* The free list is only accessed from user, non-interrupt level and
-   * is protected by a semaphore (that behaves like a mutex).
-   */
+  /* The free list is protected by the network lock */
 
   net_lock();
   conn = (FAR struct bluetooth_conn_s *)
@@ -162,9 +160,7 @@ void bluetooth_conn_free(FAR struct bluetooth_conn_s *conn)
   FAR struct bluetooth_container_s *container;
   FAR struct bluetooth_container_s *next;
 
-  /* The free list is only accessed from user, non-interrupt level and
-   * is protected by a semaphore (that behaves like a mutex).
-   */
+  /* The free list is protected by the network lock. */
 
   DEBUGASSERT(conn->bc_crefs == 0);
 

net/bluetooth/bluetooth_sendto.c

@@ -73,7 +73,7 @@
  ****************************************************************************/
 
 /* This structure holds the state of the send operation until it can be
- * operated upon from the interrupt level.
+ * operated upon from the event handler.
  */
 
 struct bluetooth_sendto_s