ARM: SoC: convert Exynos4 to SMP operations

Convert Exynos4 to use struct smp_operations to provide its SMP
and CPU hotplug operations.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>