ARM: SoC: convert Tegra to SMP operations

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

Tested on Harmony.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>