Refactor scalar 3x3s2c3 HWC->HWC2CHW dconv, add 3x3s2c3 HWC dconv

- Unify naming of variables in 3x3s2c3 HWC->HWC2CHW dconv with NEONFMA version
- Add HWC->HWC version of the micro-kernel

PiperOrigin-RevId: 283855944
diff --git a/src/xnnpack/conv.h b/src/xnnpack/conv.h
index a59afcd..18774f4 100644
--- a/src/xnnpack/conv.h
+++ b/src/xnnpack/conv.h
@@ -37,6 +37,7 @@
 
 DECLARE_F32_CONV_HWC_UKERNEL_FUNCTION(xnn_f32_conv_hwc_ukernel_3x3s2p1c3x8__neonfma_2x2)
 DECLARE_F32_CONV_HWC_UKERNEL_FUNCTION(xnn_f32_conv_hwc_ukernel_3x3s2p1c3x4__neonfma_2x2)
+DECLARE_F32_CONV_HWC_UKERNEL_FUNCTION(xnn_f32_conv_hwc_ukernel_3x3s2p1c3x4__scalar_1x1)
 
 
 #define DECLARE_F32_CONV_HWC2SPCHW_UKERNEL_FUNCTION(fn_name) \