sched: Fix comments to make them DocBook happy

Docbook fails in sched_fair.c due to comments added in the asymmetric
packing patch series.

This fixes these errors. No code changes.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <24737.1276135581@neuling.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>