refactor: Rename SVE-specific files In preparation to the SME support patches, rename the SVE-specific files to something a bit more meaningful that can be shared with the SME code. In this case, I've renamed the "sve" in the names to "scalable". No functional changes. Regression-tested on aarch64-linux Ubuntu 22.04/20.04. Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>