IVGCVSW-3697 Add Support for ANEURALNETWORKS_ARG[MAX|MIN] to HAL 1.2 Driver

!armnn:2313

Signed-off-by: Francis Murtagh <francis.murtagh@arm.com>
Change-Id: I543136e4e2ef9aece1378d2642064cc585246645
diff --git a/1.2/HalPolicy.hpp b/1.2/HalPolicy.hpp
index d611102..1f0b54d 100644
--- a/1.2/HalPolicy.hpp
+++ b/1.2/HalPolicy.hpp
@@ -35,6 +35,11 @@
 
     static bool ConvertAdd(const Operation& operation, const Model& model, ConversionData& data);
 
+    static bool ConvertArgMinMax(const Operation& operation,
+                                 const Model& model,
+                                 ConversionData& data,
+                                 armnn::ArgMinMaxFunction argMinMaxFunction);
+
     static bool ConvertAveragePool2d(const Operation& operation, const Model& model, ConversionData& data);
 
     static bool ConvertBatchToSpaceNd(const Operation& operation, const Model& model, ConversionData& data);