* Fix the compiling error which occurs when specify the ddk_root path and build for huawei NPU.

* Refine the registration of op bridges and make it similar to the registration of op and kernel.

* Refine the interfaces of the graph and node for op bridges, and support creating constant and data node automatically according to the attribute 'persistable' of the target tensor.

* Add the unit test of the scale and softmax op bridge for NPU.

test=develop

* Support multiple types for XPU and NPU op bridges

* Add lookup_table, gather, slice, stack and scale op bridges for supporting BERT

* Fix the definition of lookup_table kernel for X86

test=develop

test=develop

test=develop

* [XPU] add transpose bridge and unit test

test=develop

[LITE][NPU][XPU] Refine subgraph pass, and support NPU/XPU model generation at execution time (#2576)

* [XPU] update conv padding

test=develop

* [XPU] exclude xpu for passes

test=develop

* fix conv padding compute

test=develop

* [NPU] update 2-pad to 4-pad for conv and conv_transpose

test=develop

* reuse UpdatePadding code

test=develop

* fix conv 2-pad to 4-pad

* fix compute conv shape

* fix pad, test=develop

* change conv_depthwise_3x3s1_fp.cc name to conv3x3s1p01_depthwise_fp32.cc to distinguish between conv3x3s1_depthwise_fp32.cc

* delete printf note in conv3x3s1, test=develop

* delete printf note, test=develop

* delete gem_sdot.h, test=develop

it is coped from __gemm_sdot_meta_.h

* update compute padding, test=develop

* fix padding size, must be 2 or 4. test=develop

* fix format in operators/conv_op.cc, test=develop

* change #if 0 to #if 1, test=develop

* put 2-pad to 4-pad in AttachImpl, test=develop

* fix clang-format error inn tests/math/connv_compute_test, test=develop

* fix x86 test result error, test=develop

* add asymmetric padding test case in liite/tests/math/conv_compute.cc, test=develop

* change paddings type to support dynamically modify, test=develop

* fix x86 build error in connv_compute_test, test=develop

* fix opencl build error, test=develop

* fix oopencl build error, test=develop

* fix  opencl/conv_compute build error, test=develop

* fix  opencl/conv_compute build error, test=develop

* fix format in kernels/opencl/conv_computte_ttest,test=develop

* fix build error, test=develop

fix build error in kernels/x86/conv_compute.h

* fix pooling bug and speed

* fix build error

* delete VLOGin pool, test=develop

* add openmp, test=develop

* fix lite/kernels/arm/pool_compute_test basic_pooling compute error bug, test=develop

* update pooling 2-pad to 4-pad, test=develop

* fix 2-pad to 4-pad in operators/pool_op.h, AttachKernel will set param, so 2-pad to 4-pad funcs should put in AttachKernel. test=ddevellop

* put 2-pad to 4-pad in AttachImpl, test=develop

* according to reviews, fix some format error. test=develop

* fix format errorr, add (). test=develop

* change paddings type to support dynamically modify, test=develop

* update padding type int other devices, test=develop

* fix x8d build error on shared_ptr, test=ddevelop

* fix formmat in operators pool_op.cc, test=develop

* [XPU] add batchnorm op bridge and unit test

test=develop

* fix DMLC_USE_GLOG

test=develop

test=develop

test=develop

* [XPU] add mul op bridge and unit test

test=develop

* use tmp tensor for transposed y

test=develop

test=develop

* Initial support for XPU
* Fix compiling errors of XPU
* Move XPU op kernel bridges from backends to kernels to fix deps order
* Change the namespace and directory of XPU bridges
* Add XPU SDK
* Fix header files and namespace of XPU SDK
* Add unit tests for relu and conv2d ops
* Restore the modification of paddle_api_test
* Supports simple model which contains only a relu layer
* Add compiling scripts for XPU
* Fix compiling errors of XPU
* Add comments for XPU LoadModel and BuildModel