sched/fair: Clean up the __clear_buddies_*() functions

Slightly easier code flow, no functional changes.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1328936700.2476.17.camel@laptop


Signed-off-by: Ingo Molnar <mingo@kernel.org>