sched: change update_sg_lb_stats to h_nr_running
Since update_sg_lb_stats is used to calculate sched_group load
difference of cfs type task, it should use h_nr_running instead of
nr_running of rq.
Signed-off-by: Lei Wen <leiwen@marvell.com>

Signed-off-by: GuneetAtwal <harjinder767@gmail.com>