[clang] [llvm] [ARM] Armv8-R does not require fp64 or neon. (PR #88287)

[Chris Copeland via llvm-commits]

chrisnc wrote:

@davemgreen yes, this does change the cortex-r52 default features as well. The problem is that the cortex-r52 is the "default" CPU for armv8r (probably because it's the only one), so if I don't reduce the feature set of that CPU, armv8r will continue to imply features that are not true of all processors in that family. I can add this to the release notes if there's no other way to achieve what is needed here. Would removing the default CPU for armv8r be acceptable?
Regardless, this is an intentional behavior change because currently you get all neon and dp features just by using this architecture, so I can add release notes.

https://github.com/llvm/llvm-project/pull/88287