[CPU][x86] add support for sink input of SDPA

[tiger100256-hu]

Details:

• extend the softmax kernel API to make it support sink input
• in the reference implementation of sink input, there are 3 operations, cat, softmax, drop, because cat and drop will make attention_weight shape changed, so modify softmax API maybe a good way to reduce memory allocation and movement
• reference1: https://github.com/huggingface/transformers/blob/main/src/transformers/models/gpt_oss/modeling_gpt_oss.py#L258-L264
• reference2: https://github.com/openvinotoolkit/openvino/pull/31786/files

Tickets:

• CVS-173533

[zhangYiIntel]

The sink input is an optional parameter, if we decide to pass this parameter from SDPA cpu node to inside kernels, it's better to explicitly pass valid pointer/Plaintensor or nullptr/Plaintensor() to kernels to avoid misusage of this parameter.

[zhangYiIntel]

LGTM

[yuxu42]

Hi @maxnick could you please take a review? Thanks!

[maxnick]

Please add a short comment about the purpose of this sink input and what should be set if there is no sink input.

[tiger100256-hu]

already add comment, please help to check it, thanks

[maxnick]

PR is waiting performance checks.