make conv2d bp filter stride attr len 4

mindspore/ops/operations/_grad_ops.py

@@ -174,9 +174,9 @@ class Conv2DBackpropFilter(PrimitiveWithInfer):
         pad_mode = pad_mode.upper()
         self.add_prim_attr('pad_mode', pad_mode)
         self.pad = pad
-        if isinstance(stride, tuple) and len(stride) == 4:
-            self.stride = (stride[2], stride[3])
-            self.add_prim_attr('stride', self.stride)
+        if isinstance(stride, tuple) and len(stride) == 2:
+            self.stride = stride
+            self.add_prim_attr('stride', (1, 1, self.stride[0], self.stride[1]))
         self.dilation = dilation
         self.group = group
         self.add_prim_attr('data_format', "NCHW")