[Fix] remove unnecessary spliting in the cached chunk (#4935)

* remove unnecessary spliting in the cached chunk

* remove unnecessary spliting in the cached chunk

topi/python/topi/x86/depthwise_conv2d.py

@@ -223,12 +223,12 @@ def _schedule_depthwise_conv2d_NCHWc_impl(s, cfg, data_vec, kernel_vec, conv_out
     s[C].parallel(parallel_axis)
     s[CC].compute_at(s[C], ow_chunk)
 
+    # the ow axis in the cached block CC is the ow_block in C
     _, ic_chunk, oh, ow, ic_block = s[CC].op.axis
     kh, kw = s[CC].op.reduce_axis
-    ow_chunk, ow_block = s[CC].split(ow, factor=tile_ow)
-    s[CC].reorder(ic_chunk, oh, kh, kw, ow_block, ic_block)
+    s[CC].reorder(ic_chunk, oh, kh, kw, ow, ic_block)
     s[CC].vectorize(ic_block)
-    s[CC].unroll(ow_block)
+    s[CC].unroll(ow)
 
     if C != O:
         out_ndim = len(s[O].op.axis)