Impact: cleanup

lapic_timer_setup is self-protected with local_irq_save/restore
no need to use them in caller and levt is the per-cpu variable so
no concurrent access from another cpu.
Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Acked-by: N"Maciej W. Rozycki" <macro@linux-mips.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>