Move ot subfolder. Prepare to add other op of quantization

library/src/tensor_operation_instance/gpu/quantization/CMakeLists.txt

 add_instance_library(device_quantization_instance
-    device_conv2d_xdl_bias_perchannel_quantization_int8_instance.cpp
-    device_conv2d_xdl_bias_perlayer_quantization_int8_instance.cpp
-    device_conv2d_xdl_perchannel_quantization_int8_instance.cpp
-    device_conv2d_xdl_perlayer_quantization_int8_instance.cpp
+    conv2d_fwd/device_conv2d_xdl_bias_perchannel_quantization_int8_instance.cpp
+    conv2d_fwd/device_conv2d_xdl_bias_perlayer_quantization_int8_instance.cpp
+    conv2d_fwd/device_conv2d_xdl_perchannel_quantization_int8_instance.cpp
+    conv2d_fwd/device_conv2d_xdl_perlayer_quantization_int8_instance.cpp
 )