Final cpumask conversion for x86

After these patches, I can build allmodconfig on 32 and 64 bit x86 with the obsolete cpumask function definitions and names configured out. After 3 more patches, we can finally allocate offstack cpumasks with less than NR_CPUS bits.

I'd appreciate it if the various maintainers picked these up (most are simple); Andrew, you seem best poised to annoy the others, do you want to take these?

Thanks!
Rusty.