COMPMID-1890 Compile failure (uninitialized warning) with g++7.3

Change-Id: I518654387610316f03fbf8a72776d8f7789b29cd
Reviewed-on: https://review.mlplatform.org/525
Reviewed-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/core/NEON/kernels/NEReductionOperationKernel.cpp b/src/core/NEON/kernels/NEReductionOperationKernel.cpp
index d88717a..f0209a3 100644
--- a/src/core/NEON/kernels/NEReductionOperationKernel.cpp
+++ b/src/core/NEON/kernels/NEReductionOperationKernel.cpp
@@ -443,7 +443,7 @@
         auto vec_res_value3 = vdupq_n_u32(static_cast<uint32_t>(0.f));
         auto vec_res_value4 = vdupq_n_u32(static_cast<uint32_t>(0.f));
 
-        uint8x16_t vec_res_value;
+        uint8x16_t vec_res_value = { 0 };
         if(op == ReductionOperation::ARG_IDX_MAX || op == ReductionOperation::ARG_IDX_MIN)
         {
             vec_res_value = wrapper::vdup_n(*input.ptr(), wrapper::traits::vector_128_tag{});
@@ -530,7 +530,7 @@
 
         execute_window_loop(in_slice, [&](const Coordinates & id)
         {
-            neon_vector vec_res_value;
+            neon_vector vec_res_value = { 0 };
             if(op == ReductionOperation::ARG_IDX_MAX || op == ReductionOperation::ARG_IDX_MIN)
             {
                 vec_res_value = wrapper::vloadq(reinterpret_cast<T *>(input.ptr()));