Revert "smp/cpumask: Make CONFIG_CPUMASK_OFFSTACK=y usable without debug dependency"

Revert "smp/cpumask: Make CONFIG_CPUMASK_OFFSTACK=y usable without debug dependency"

This reverts commit 180c674bb7ebc3c2c3455004745564817a46f043.

Revert it until Linus's concerns are addressed: this option should not
allow nonsensical CONFIG_CPUMASK_OFFSTACK and CONFIG_NR_CPUS values, and
it should probably select sane defaults as well.

Cc: Josh Boyer <jwboyer@fedoraproject.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-etcruvuw9neycYf0Rripxrjv@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>