CMSIS-NN: Fix warnings

1. Doxygen warnings are fixed

2. Sign conversion warnings(-Wsign-conversion) and -Wextra warnings
   are fixed for TFLu compliant MVE APIs

Change-Id: I22ee8cd4ff4c94c92d9659504fc4c24d2b5ae441

Source/BasicMathFunctions/arm_add_q7.c

@@ -1,15 +1,5 @@
-/* ----------------------------------------------------------------------
- * Project:      CMSIS DSP Library
- * Title:        arm_add_q7.c
- * Description:  Q7 vector addition
- *
- * $Date:        18. March 2019
- * $Revision:    V1.6.0
- *
- * Target Processor: Cortex-M cores
- * -------------------------------------------------------------------- */
 /*
- * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
+ * Copyright (C) 2010-2020 ARM Limited or its affiliates. All rights reserved.
  *
  * SPDX-License-Identifier: Apache-2.0
  *
@@ -26,6 +16,17 @@
  * limitations under the License.
  */
 
+/* ----------------------------------------------------------------------
+ * Project:      CMSIS DSP Library
+ * Title:        arm_add_q7.c
+ * Description:  Q7 vector addition
+ *
+ * $Date:        May 29, 2020
+ * $Revision:    V1.6.1
+ *
+ * Target Processor: Cortex-M cores
+ * -------------------------------------------------------------------- */
+
 #include "arm_math.h"
 
 /**