Merge pull request #7588 from hvy/chx-ch-clipped-relu

Use `chainerx.clipped_relu` in `F.clipped_relu`

chainer/functions/activation/clipped_relu.py

@@ -39,7 +39,7 @@ def check_type_forward(self, in_types):
 
     def forward_chainerx(self, inputs):
         x, = inputs
-        return chainerx.minimum(chainerx.maximum(0, x), self.cap),
+        return chainerx.clipped_relu(x, self.cap),
 
     def forward_cpu(self, inputs):
         self.retain_inputs((0,))