Optee a80 porting

Optee-os add a80 platform support.

This request have three patchs, The patchs summary:
1.gic driver add gic_cpu_init function, mainly for secondary cpu secure stage initialization,
2.Make uart driver more portable, add common console.h and console basic functions,
3.Add plat-sunxi support, the initial version, running on A80 Optimus board.

All patchs only tested on A80 Optimus board, Due to the lack of platform.
Mayeb the uart driver patch should be test on vexpress platform.
You are right,  plat-sunxi/core_bootcfg.c is copy from plat-stm/core_bootcfg.c.
This file I mainly modify the memory configurations table, Not carefully look at other code.
I will fix the wrong messages. But plat-stm and plat-vexpress have the same message error.
Can I fix plat-stm and vexpress at the same time? 
Avoid similar problems appear when the new platform porting.