x86: cpumask: x86 mmio-mod.c use cpumask_var_t for downed_cpus
x86: cpumask: x86 mmio-mod.c use cpumask_var_t for downed_cpus

Impact: cleanup, reduce memory usage for CONFIG_CPUMASK_OFFSTACK=y

Part of the "getting rid of obsolete cpumask_t" patch:

 1) Use cpumask_var_t: this is a pointer if CONFIG_CPUMASK_OFFSTACK=y
 2) Call alloc_cpumask_var() on first entry into enter_uniprocessor()
 3) Use modern cpumask_* functions.

Signed-off-by: Rusty Russell <df9728c9e5104131c08c7adb03af425394842596@rustcorp.com.au>
Cc: Pekka Paalanen <57fbf5561796ac3f40d7fbf8e6b649ed5638552e@iki.fi>
LKML-Reference: <200903111633.55952.df9728c9e5104131c08c7adb03af425394842596@rustcorp.com.au>
Signed-off-by: Ingo Molnar <9dbbbf0688fedc85ad4da37637f1a64b8c718ee2@elte.hu>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs