irq: multilevel: fix `irq_parent_level_3()` #139696

Job	Run time
twister-build-prep	4m 11s
twister-build (1)	40m 4s
twister-build (2)	40m 43s
twister-build (3)	50m 43s
twister-build (4)	39m 44s
twister-build (5)	28m 22s
twister-build (6)	48m 19s
Publish Unit Tests Results	18s
Check Twister Status / all jobs passed	1s
	4h 12m 25s

Provide feedback