ARM: 8568/1: reboot: remove duplicated local_irq_disable()

Once entering machine_halt() and machine_restart(), local_irq_disable()
is called, and local irq is kept disabled, so the local_irq_disable()
at the end of these two functions are not necessary, remove it.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>