[llvm] [AArch64] Initial sched model for Neoverse N3 (PR #106371)

[via llvm-commits]

FLZ101 wrote:

> I am checking others with N2ScheModel and V2SchedModel as references. May take some time.

Done. Besides changing some `L`s, I also adjust some `I`s and perform a rebase.

https://github.com/llvm/llvm-project/pull/106371