* add reduce_sum_int64 and reduce_sum_int8 xpu kernels

* [PHI] add clip grad kernel with support type float32 and int32

* [PHI unittest] add clip_grad unit test

* adapt code to clang-format

* update xpu api output with clip_grad api

* remove int8 support of reduce_sum xpu kernel since it can not pass unit tests

* adapt license date, add code for XPUDataType convertion

* add int8 support of reduce_sum

* add reduce_sum unit tests for dtype int64, int8, and add more test cases

* update license date

* remove buggy bitwise and, or and xor xpu kernels, refine bitwise not xpu kernel

* change license date