Remove redundant fake-quants for the object detection model.

PiperOrigin-RevId: 456554091

official/projects/qat/vision/modeling/factory.py

@@ -175,7 +175,6 @@ def build_qat_retinanet(
           clone_function=_clone_function_for_fpn,
       )
       decoder = tfmot.quantization.keras.quantize_model(decoder)
-      decoder = tfmot.quantization.keras.remove_input_range(decoder)
 
     head = model.head
     if quantization.quantize_detection_head:

official/projects/qat/vision/modeling/heads/dense_prediction_heads.py

@@ -54,7 +54,7 @@ class SeparableConv2DQuantized(tf.keras.layers.Layer):
     depthwise_conv2d_quantized = helper.quantize_wrapped_layer(
         tf.keras.layers.DepthwiseConv2D,
         configs.Default8BitConvQuantizeConfig(
-            ['depthwise_kernel'], [], True))
+            ['depthwise_kernel'], ['activation'], True))
     conv2d_quantized = helper.quantize_wrapped_layer(
         tf.keras.layers.Conv2D,
         configs.Default8BitConvQuantizeConfig(