Add LUT for quantized sigmoid function

* Move LUT implementation to a seperate file. It will be used
  for both QASYMM8 and QASYMM8_SIGNED.
* Fix wrong constant value related to QASYMM8_SIGNED leaky ReLU
  in 32-bit build.

Resolves: COMPMID-5464
Signed-off-by: Viet-Hoa Do <viet-hoa.do@arm.com>
Change-Id: I2b24d52409a38f1b66fd532f431eff8a9e4547b6
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/8066
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Gunes Bayir <gunes.bayir@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/cpu/kernels/activation/list.h b/src/cpu/kernels/activation/list.h
index b2322a6..3850d4d 100644
--- a/src/cpu/kernels/activation/list.h
+++ b/src/cpu/kernels/activation/list.h
@@ -31,8 +31,8 @@
 #define DECLARE_ACTIVATION_KERNEL(func_name) \
     void func_name(const ITensor *src, ITensor *dst, const ActivationLayerInfo &act_info, const Window &window)
 
+DECLARE_ACTIVATION_KERNEL(neon_q8_activation_lut);
 DECLARE_ACTIVATION_KERNEL(neon_qasymm8_activation);
-DECLARE_ACTIVATION_KERNEL(neon_qasymm8_activation_lut);
 DECLARE_ACTIVATION_KERNEL(sve2_qasymm8_activation);
 DECLARE_ACTIVATION_KERNEL(neon_qasymm8_signed_activation);
 DECLARE_ACTIVATION_KERNEL(sve2_qasymm8_signed_activation);