fix #4670: add bias for fc layer (#4801)

python/tvm/relay/testing/mobilenet.py

@@ -120,7 +120,9 @@ def mobile_net(num_classes=1000, data_shape=(1, 3, 224, 224),
     pool = relay.nn.global_avg_pool2d(data=body, layout=layout)
     flatten = relay.nn.batch_flatten(data=pool)
     weight = relay.var('fc_weight')
+    bias = relay.var('fc_bias')
     fc = relay.nn.dense(data=flatten, weight=weight, units=num_classes)
+    fc = relay.nn.bias_add(fc, bias)
     softmax = relay.nn.softmax(data=fc)
     return relay.Function(relay.analysis.free_vars(softmax), softmax)