sched/balancing: Update comments in 'struct sg_lb_stats' and 'struct sd_lb_stats'

- Align for readability
- Capitalize consistently

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20240308105901.1096078-11-mingo@kernel.org