Netsocket: Add required header file and namespace element instead add all

Author: Deepika

features/netsocket/EMACInterface.cpp

@@ -15,6 +15,7 @@
  */
 
 #include "EMACInterface.h"
+using namespace mbed;
 
 /* Interface implementation */
 EMACInterface::EMACInterface(EMAC &emac, OnboardNetworkStack &stack) :

features/netsocket/EMACInterface.h

@@ -18,7 +18,6 @@
 #define EMAC_INTERFACE_H
 
 #include "nsapi.h"
-#include "rtos.h"
 #include "EMAC.h"
 #include "OnboardNetworkStack.h"
 

features/netsocket/EthernetInterface.h

@@ -18,7 +18,6 @@
 #define ETHERNET_INTERFACE_H
 
 #include "nsapi.h"
-#include "rtos.h"
 #include "EMACInterface.h"
 
 

features/netsocket/TCPServer.cpp

@@ -15,7 +15,8 @@
  */
 
 #include "TCPServer.h"
-#include "mbed.h"
+
+using mbed::Callback;
 
 TCPServer::TCPServer()
 {