sched/fair: Clean up the tunable parameter definitions

No change in functionality:

 - align the default values vertically to make them easier to scan
 - standardize the 'default:' lines
 - fix minor whitespace typos

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>