[llvm] [llvm][ARM][NFC] Renaming FeaturePrefLoopLogAlign (PR #109932)

[Tomas Matheson via llvm-commits]

https://github.com/tmatheson-arm commented:

Personally I would just kept it consistent with the subtarget feature spelling, e.g. `FeatureLoopAlign` to match `loop-align`. But I don't feel that strongly. If you're going to stick with the current suggestion then maybe expand "Pref" to "Prefer" since it only saves two characters.

https://github.com/llvm/llvm-project/pull/109932