Fix ReductionLayer FP16 for armv8a multi_isa builds

- Enable FP16 code when building multi_isa for armv8a architecture in
  order to run on higher architectures e.g. 8.2, 8.6.
- When running this build on v8 the validation will stop it flagging
  that the arch does not support FP16.

Resolves: COMPMID-7013
Signed-off-by: Ramy Elgammal <ramy.elgammal@arm.com>
Change-Id: I0d445e2fade31c1156d7a6e142edf2a7f84d3622
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/11544
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Pablo Marquez Tello <pablo.tello@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 74be9e5..e47b5cb 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -812,6 +812,11 @@
 	cpu/kernels/range/generic/neon/fp16.cpp
 	cpu/kernels/range/generic/neon/fp32.cpp
 	cpu/kernels/range/generic/neon/integer.cpp
+	cpu/kernels/reduction_layer/generic/neon/fp16.cpp
+	cpu/kernels/reduction_layer/generic/neon/fp32.cpp
+	cpu/kernels/reduction_layer/generic/neon/integer.cpp
+	cpu/kernels/reduction_layer/generic/neon/qasymm8.cpp
+	cpu/kernels/reduction_layer/generic/neon/qasymm8_signed.cpp
 	cpu/kernels/roialign/generic/neon/fp16.cpp
 	cpu/kernels/roialign/generic/neon/fp32.cpp
 	cpu/kernels/roialign/generic/neon/qasymm8.cpp