COMPMID-2796: Add support for QASYMM8_SIGNED in NEActivationLayer and NEPReluLayer

Change-Id: I089fd19a6beab7779d690bc9ace327f661c2753d
Signed-off-by: Michalis Spyrou <michalis.spyrou@arm.com>
Reviewed-on: https://review.mlplatform.org/c/2407
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Michele Di Giorgio <michele.digiorgio@arm.com>
diff --git a/arm_compute/runtime/NEON/functions/NEActivationLayer.h b/arm_compute/runtime/NEON/functions/NEActivationLayer.h
index cd9b22d..95901dc 100644
--- a/arm_compute/runtime/NEON/functions/NEActivationLayer.h
+++ b/arm_compute/runtime/NEON/functions/NEActivationLayer.h
@@ -59,7 +59,7 @@
      * @note If the output tensor is a nullptr or is equal to the input, the activation function will be performed in-place
      *
      * @param[in, out] input           Source tensor. In case of @p output tensor = nullptr, this tensor will store the result
-     *                                 of the activation function. Data types supported: QASYMM8/QSYMM16/F16/F32.
+     *                                 of the activation function. Data types supported: QASYMM8/QASYMM8_SIGNED/QSYMM16/F16/F32.
      * @param[out]     output          Destination tensor. Data type supported: same as @p input
      * @param[in]      activation_info Activation layer parameters.
      */
@@ -68,7 +68,7 @@
     /** Static function to check if given info will lead to a valid configuration of @ref NEActivationLayer
      *
      * @param[in] input    Source tensor info. In case of @p output tensor info = nullptr, this tensor will store the result
-     *                     of the activation function. Data types supported: QASYMM8/QSYMM16/F16/F32.
+     *                     of the activation function. Data types supported: QASYMM8/QASYMM8_SIGNED/QSYMM16/F16/F32.
      * @param[in] output   Destination tensor info. Data type supported: same as @p input
      * @param[in] act_info Activation layer information.
      *
diff --git a/arm_compute/runtime/NEON/functions/NEPReluLayer.h b/arm_compute/runtime/NEON/functions/NEPReluLayer.h
index c0a1df4..102a165 100644
--- a/arm_compute/runtime/NEON/functions/NEPReluLayer.h
+++ b/arm_compute/runtime/NEON/functions/NEPReluLayer.h
@@ -40,14 +40,14 @@
 public:
     /** Set the input and output tensor.
      *
-     * @param[in]  input  Source tensor. Data types supported: QASYMM8/F16/F32.
+     * @param[in]  input  Source tensor. Data types supported: QASYMM8/QASYMM8_SIGNED/F16/F32.
      * @param[in]  alpha  Source alpha tensor. Data types supported: same of @p input.
      * @param[out] output Destination tensor. Data type supported: same as @p input
      */
     void configure(const ITensor *input, const ITensor *alpha, ITensor *output);
     /** Static function to check if given info will lead to a valid configuration of @ref NEPReluLayer
      *
-     * @param[in] input  Source tensor info. Data types supported: QASYMM8/F16/F32.
+     * @param[in] input  Source tensor info. Data types supported: QASYMM8/QASYMM8_SIGNED/F16/F32.
      * @param[in] alpha  Source alpha tensor info. Data types supported: same of @p input.
      * @param[in] output Destination tensor info. Data type supported: same as @p input
      *