powerpc/book3e: Disable interrupt after preempt_schedule_irq

powerpc/book3e: Disable interrupt after preempt_schedule_irq

commit 572177d7c77db1981ba2563e01478126482c43bc upstream.

In preempt case current arch_local_irq_restore() from
preempt_schedule_irq() may enable hard interrupt but we really
should disable interrupts when we return from the interrupt,
and so that we don't get interrupted after loading SRR0/1.

Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>