ARM: SoC: convert ux500 to SMP operations

Convert ux500 platforms to use struct smp_operations to provide
their SMP and CPU hotplug operations.

Cc: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: srinidhi kasagar <srinidhi.kasagar@stericsson.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>