sched/fair: Fix update of rd->sg_overutilized

sg_overloaded is used instead of sg_overutilized to update
rd->sg_overutilized.

Fixes: 4475cd8b

 ("sched/balancing: Simplify the sg_status bitmask and use separate ->overloaded and ->overutilized flags")
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20240404155738.2866102-1-vincent.guittot@linaro.org