percpu: update incorrect comment for this_cpu_*() operations

this_cpu_*() ops have been protected against both preemption and
interrupts for quite a while now.  We apparently forgot to update the
comment.  Fix it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
1 file changed