This patch adds the following features defined by Arm SVE2 architecture
extension:
sve2, sve2-aes, sve2-sm4, sve2-sha3, bitperm
For existing CPUs these features are declared as unsupported to prevent
scheduler errors.
The specification can be found here:
https://developer.arm.com/docs/ddi0602/latest
It might be a bit long, but I'd prefer sve2-bitperm here, to avoid the kind of situation we have in the ARM backend with hwdiv / hwdiv-arm.