ARM: hi3xxx: add smp support

Enable SMP support on hi3xxx platform

Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Tested-by: Zhang Mingjun <zhang.mingjun@linaro.org>
Tested-by: Li Xin <li.xin@linaro.org>
Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>
[khilman: fix checkpatch errors]
Signed-off-by: Kevin Hilman <khilman@linaro.org>