sched.c : Fix Warning
ARM: fix warning on uninitialized offset.un

arch/arm/mm/alignment.c: In function 'do_alignment':
arch/arm/mm/alignment.c:327:15: warning: 'offset.un' may be used uninitialized in this function [-Wmaybe-uninitialized]
arch/arm/mm/alignment.c:749:21: note: 'offset.un' was declared here