arm: "Correct" the spelling of flavor.

arm: "Correct" the spelling of flavor.

In US English, flavor is spelled flavor, not flavour. The choice of
US spelling is arbitrary but consistent with gem5's history and the
rest of the code base.

Also fix a couple small style issues.

Change-Id: I307f8458fec5918a6fc34f938a4c12955d4d0565
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/25010
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>