COMPMID-2994: Add support QASYMM8_SIGNED in NEElementwiseSquareDiff

Updated interface documention and added precommit tests.

Change-Id: I6d4fe250eb72d3daff977e5a98c1086692e3654a
Signed-off-by: morgolock <pablo.tello@arm.com>
Reviewed-on: https://review.mlplatform.org/c/2580
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
diff --git a/arm_compute/runtime/NEON/functions/NEElementwiseOperations.h b/arm_compute/runtime/NEON/functions/NEElementwiseOperations.h
index 9499867..eec9bb9 100644
--- a/arm_compute/runtime/NEON/functions/NEElementwiseOperations.h
+++ b/arm_compute/runtime/NEON/functions/NEElementwiseOperations.h
@@ -33,7 +33,7 @@
 
 /** Basic function to run @ref NEArithmeticOperationKernel for max
  *
- * @note The tensor data type for the inputs must be QASYMM8/S16/F16/S32/F32.
+ * @note The tensor data type for the inputs must be QASYMM8/QASYMM8_SIGNED/S16/F16/S32/F32.
  * @note The function performs a max operation between two tensors.
  */
 class NEElementwiseMax : public INESimpleFunction
@@ -59,8 +59,8 @@
 
 /** Basic function to run @ref NEArithmeticOperationKernel for min
  *
- * @note The tensor data type for the inputs must be QASYMM8/S16/F16/S32/F32.
- * @note The function performs a max operation between two tensors.
+ * @note The tensor data type for the inputs must be QASYMM8/QASYMM8_SIGNED/S16/F16/S32/F32.
+ * @note The function performs a min operation between two tensors.
  */
 class NEElementwiseMin : public INESimpleFunction
 {
@@ -85,7 +85,7 @@
 
 /** Basic function to run @ref NEArithmeticOperationKernel for squared difference
  *
- * @note The tensor data type for the inputs must be QASYMM8/S16/F16/S32/F32.
+ * @note The tensor data type for the inputs must be QASYMM8/QASYMM8_SIGNED/S16/F16/S32/F32.
  * @note The function performs a squared different operation between two tensors (i.e., out[i] = (in1[i] - in2[i])^2
  */
 class NEElementwiseSquaredDiff : public INESimpleFunction
@@ -93,14 +93,14 @@
 public:
     /** Initialise the kernel's inputs, output and conversion policy.
      *
-     * @param[in, out] input1 First tensor input. Data types supported: QASYMM8/S16/F16/S32/F32.
+     * @param[in, out] input1 First tensor input. Data types supported: QASYMM8/QASYMM8_SIGNED/S16/F16/S32/F32.
      * @param[in, out] input2 Second tensor input. Data types supported: Same as @p input1.
      * @param[out]     output Output tensor. Data types supported: Same as @p input1.
      */
     void configure(ITensor *input1, ITensor *input2, ITensor *output);
     /** Static function to check if given info will lead to a valid configuration of @ref NEArithmeticOperationKernel for squared difference
      *
-     * @param[in] input1 First tensor input info. Data types supported: QASYMM8/S16/F16/S32/F32.
+     * @param[in] input1 First tensor input info. Data types supported: QASYMM8/QASYMM8_SIGNED/S16/F16/S32/F32.
      * @param[in] input2 Second tensor input info. Data types supported: Same as @p input1.
      * @param[in] output Output tensor info. Data types supported: Same as @p input1.
      *