ARM: restart: remove local_irq_disable() from within arch_reset()

IRQs are already disabled by the time arch_reset() is called, so these
calls to local_irq_disable() instead arch_reset() are redundant.  Remove
them.

Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>