Remove use of `std::clamp`

  * Introduced in IVGCVSW-7853 (causes issues with older compilers)

Signed-off-by: Declan-ARM <decmce01@arm.com>
Change-Id: I945b7be5e0e8fe47c8d4859d1db40b5130392363
diff --git a/src/armnn/layers/MeanLayer.cpp b/src/armnn/layers/MeanLayer.cpp
index 8e6d9e0..6a041c2 100644
--- a/src/armnn/layers/MeanLayer.cpp
+++ b/src/armnn/layers/MeanLayer.cpp
@@ -78,7 +78,7 @@
     const TensorShape& input = inputShapes[0];
 
     auto inputDims = input.GetNumDimensions();
-    if (inputDims != std::clamp(inputDims, 1u, 4u))
+    if (inputDims < 1 || inputDims > 4)
     {
         throw armnn::Exception("ReduceLayer: Reduce supports up to 4D input.");
     }
diff --git a/src/armnn/layers/ReduceLayer.cpp b/src/armnn/layers/ReduceLayer.cpp
index 9fbbc39..d514aa6 100644
--- a/src/armnn/layers/ReduceLayer.cpp
+++ b/src/armnn/layers/ReduceLayer.cpp
@@ -52,7 +52,7 @@
     const TensorInfo& input = GetInputSlot(0).GetTensorInfo();
 
     auto inputDims = input.GetNumDimensions();
-    if (inputDims != std::clamp(inputDims, 1u, 4u))
+    if (inputDims < 1 || inputDims > 4)
     {
         throw armnn::LayerValidationException("ReduceLayer: Reduce supports up to 4D input.");
     }
@@ -73,7 +73,7 @@
     const TensorShape& input = inputShapes[0];
 
     auto inputDims = input.GetNumDimensions();
-    if (inputDims != std::clamp(inputDims, 1u, 4u))
+    if (inputDims < 1 || inputDims > 4)
     {
         throw armnn::Exception("ReduceLayer: Reduce supports up to 4D input.");
     }