sched/fair: Fix sched_avg fold

sched/fair: Fix sched_avg fold

After the robot reported a regression wrt commit: 089d84203ad4 ("sched/fair:
Fold the sched_avg update"), Shrikanth noted that two spots missed a factor
se_weight().

Fixes: 089d84203ad4 ("sched/fair: Fold the sched_avg update")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202512181208.753b9f6e-lkp@intel.com
Debugged-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251218102020.GO3707891@noisy.programming.kicks-ass.net