struct cpumask will be undefined soon with CONFIG_CPUMASK_OFFSTACK=y,
to avoid them being declared on the stack.

cpumask_bits() does what we want here (of course, this code is crap).
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
To: Thomas Gleixner <tglx@linutronix.de>