percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix

A commit in linux-next was causing boot to fail and bisection
identified the patch 4ba29684

 ("percpu: Resolve ambiguities in
__get_cpu_var/cpumask_var_").  One of the changes in that patch looks
very suspicious.  Reverting the full patch fixes boot as does this
fixlet.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>