COMPMID-3069: Fix build for armv7a on Android

Change-Id: Iefdebff9d480d3a2bb9446af9ac12edb52500916
Signed-off-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/2797
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Luca Foschiani <luca.foschiani@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/tests/validation/NEON/ReductionOperation.cpp b/tests/validation/NEON/ReductionOperation.cpp
index cd96a6a..f155e97 100644
--- a/tests/validation/NEON/ReductionOperation.cpp
+++ b/tests/validation/NEON/ReductionOperation.cpp
@@ -45,8 +45,10 @@
 /** Tolerance for float operations */
 AbsoluteTolerance<float> tolerance_f32(0.0001f);
 RelativeTolerance<float> rel_tolerance_f32(0.0001f);
+#ifdef __ARM_FEATURE_FP16_VECTOR_ARITHMETIC
 AbsoluteTolerance<float> tolerance_f16(0.1f);
 RelativeTolerance<float> rel_tolerance_f16(0.1f);
+#endif // __ARM_FEATURE_FP16_VECTOR_ARITHMETIC
 /** Tolerance for quantized operations */
 RelativeTolerance<float> tolerance_quantized(1.f);