Added missing license to header of the file

Author: Mika Leppänen

features/netsocket/emac-drivers/TARGET_NXP_EMAC/TARGET_LPCTarget/lpc17_emac.h

@@ -1,4 +1,17 @@
-
+/* Copyright (c) 2018 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 #ifndef LPC17_EMAC_H_
 #define LPC17_EMAC_H_