Impact: use new cpumask API to reduce memory and stack usage

Allocate the following local cpumasks based on the number of cpus that
are present.  References will use new cpumask API.  (Currently only
modified for x86_64, x86_32 continues to use the *_map variants.)

    cpu_callin_mask
    cpu_callout_mask
    cpu_initialized_mask
    cpu_sibling_setup_mask

Provide the following accessor functions:

    struct cpumask *cpu_sibling_mask(int cpu)
    struct cpumask *cpu_core_mask(int cpu)

Other changes are when setting or clearing the cpu online, possible
or present maps, use the accessor functions.
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>