net: Minor fix in error checking in TCP/UDP Tx drain logic

net/tcp/tcp_conn.c

@@ -747,7 +747,7 @@ void tcp_free(FAR struct tcp_conn_s *conn)
 #endif
 
   /* Because g_free_tcp_connections is accessed from user level and event
-   * processing logic, it is necessary to keep the newtork locked during this
+   * processing logic, it is necessary to keep the network locked during this
    * operation.
    */
 

net/tcp/tcp_txdrain.c

@@ -65,7 +65,7 @@
  *   Called with the write buffers have all been sent.
  *
  * Input Parameters:
- *   arg     - The semaphore that will wake up tcp_txdrain
+ *   arg     - The notifier entry.
  *
  * Returned Value:
  *   None.
@@ -178,7 +178,7 @@ int tcp_txdrain(FAR struct socket *psock,
             {
               ret = net_timedwait(&waitsem, abstime);
             }
-          while (ret == EINTR);
+          while (ret == -EINTR);
 
           /* Tear down the disconnect notifier */
 

net/udp/udp_txdrain.c

@@ -144,7 +144,7 @@ int udp_txdrain(FAR struct socket *psock,
         {
           ret = net_timedwait(&waitsem, abstime);
         }
-      while (ret == EINTR);
+      while (ret == -EINTR);
 
       /* Tear down the notifier (in case we timed out or were canceled) */