CANN: Add the basic supports of Flash Attention kernel (llama/13627)

CANN: Add the basic supports of Flash Attention kernel (llama/13627)

* cann: add the basic FA support

* cann: update the readme

* cann: update the FlashAttention with PSEShift

* cann: update the input parameters in FA

* cann: update the alibi with max_bias

* cann: add the constrints of softcap

* cann: update the docs CANN.md

* cann: update the docs CANN.md

* cann: fix typo of CANN.md

* cann: add some comments and update the CANN.md

* cann: update the CANN.md

* cann: update the inner precise for fusedInferAttention

* cann: update the constraints of flash_attn_ext on ggml-cann.cpp

* cann: clean the whitespace

* cann: clean the whitespace

* cann: add a new endline