sparc: Use preempt_schedule_irq

The low level preemption code fiddles with the PREEMPT_ACTIVE bit for
no reason and calls schedule() with interrupts disabled, which is
wrong to begin with. Remove the PREEMPT_ACTIVE fiddling and call the
proper schedule_preempt_irq() function.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/20130917183628.966769884@linutronix.de