Fix cann compilation error after llama.cpp supports dynamically loadable backends

[leo-pony]

Changes:

1. To adapt to the changes in the definition of ggml_backend_event_t, event no longer contains a backend member, and a ggml_backend_device type member is added to support dynamically loadable backends.
2. Adapt to the change of ggml_backend_cann_event_record function signature. backend is no longer passed in through event, but a ggml_backend_t type parameter is added.

Remarks:
1)This PR fix the issue: "Bug: [CANN] compile failure #9844"
2)[CANN] backend adapts to llama.cpp dynamical backend loading mechanism will be implemented in #9862

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[leo-pony]

Running inference sucessfully with two npu:

[leo-pony]

@ggerganov example/server/public/index.js seems changed last day. Server check is failed for new PR request because index.js has different from npm.reversehttp.com, and when push with new index.js download from upstream server check passed.

If it is right, I will update index.js with the content from upstream

[ggerganov]

I've opened a PR: #9895

Will merge it after the CI is green and then you can rebase.