Add QASYMM8_SIGNED support to graph examples via graph mutator

Related to COMPMID-4279

Signed-off-by: SiCongLi <sicong.li@arm.com>
Change-Id: I6c737536b4e614cc9975003acca766803f55bf0b
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/5206
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/core/Utils.cpp b/src/core/Utils.cpp
index babf1c4..8deb597 100644
--- a/src/core/Utils.cpp
+++ b/src/core/Utils.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2020 Arm Limited.
+ * Copyright (c) 2016-2021 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -330,6 +330,7 @@
         { "f16", DataType::F16 },
         { "f32", DataType::F32 },
         { "qasymm8", DataType::QASYMM8 },
+        { "qasymm8_signed", DataType::QASYMM8_SIGNED },
     };
 
 #ifndef ARM_COMPUTE_EXCEPTIONS_DISABLED