reorder struct prop_local_single to remove padding on 64 bit builds

reorder structure to remove 8 bytes of padding on 64 bit builds

(also removes 8 bytes from task_struct)

Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Cc: peterz@infradead.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>