cpumask: change cpumask_of_cpu_ptr to use new cpumask_of_cpu

  * Replace previous instances of the cpumask_of_cpu_ptr* macros
    with a the new (lvalue capable) generic cpumask_of_cpu().

Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>