AVX versions of Sigmoid evaluation stubs

PiperOrigin-RevId: 333461551
diff --git a/CMakeLists.txt b/CMakeLists.txt
index b87230d..eb3d14d 100755
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1703,7 +1703,9 @@
   src/f32-vunary/gen/vneg-avx-x16.c
   src/f32-vunary/gen/vsqr-avx-x8.c
   src/f32-vunary/gen/vsqr-avx-x16.c
-  src/math/exp-avx-p5.c)
+  src/math/exp-avx-p5.c
+  src/math/sigmoid-avx-rr2-p5-div.c
+  src/math/sigmoid-avx-rr2-lut64-p2-div.c)
 
 SET(XNNPACK_XOP_MICROKERNEL_SRCS
   src/qs8-gemm/gen/1x4c2-minmax-xop-ld64.c