* support pure bfloat16

* support bf16 linear

* update PR to pass CI

* tiny fix where_grad_kernel.cu

* add bfloat16 to selu_grad to pass CI

* fix selu grad compilation error

resort .cu headers, set clang-format not sort include block and consider .cu as main source file (#43633)

* move embeding to phi;

* update sig; test=develop

* move reset impl to phi; test=develop

* remove old register; test=develop

* fix cpu bf16 bug; test=develop

* fix lookup speed error

* polish code

* fix paddle throw type