Re-sync s.CPUFeatures with the kernel version
This fixes a build error (due to CPUFeature_Max being increased beyond 64 in RiscOS/Sources/Kernel!55 (merged)), and ensures the correct values are reported for the new flags.
Also, add a check to ensure that any addition of new flags will result in a build failure. CallASWI blindly claims that it reports the correct value for all flags, even ones it doesn't contain explicit code for. So if new flags are added which need to be "true" on old CPUs (like CP15_DFAR_DFSR_writable), CallASWI would mistakenly report a "false" value. By forcing a build failure whenever new flags are added to the kernel, we should get some good protection against this kind of mistake.
Admin: Builds, untested.