[llvm] [AArch64] Add Ampere1B scheduling/pipeline model (PR #81338)

[Philipp Tomsich via llvm-commits]

ptomsich wrote:

> Looks neat and tidy. Can't see anything obviously wrong. LGTM.

Thanks! Guess it shows that this isn't our first scheduling model ;-)

https://github.com/llvm/llvm-project/pull/81338