Merge init_task_32/64.c.
Move 64bit per cpu data orig_ist to setup64.c.

[ mingo: fixed checkpatch trivialities. ]
Signed-off-by: NHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>