Support ARM for Hi3798 V200+

[yangfl]

Hi3798 V200+ come from Cortex-A9. Of course AArch64 is preferred, but hisi sdk also comes from ARM32 support for those chips.

Should we add those chips for ARM32?

[185264646]

Hi3798 V200+ come from Cortex-A9. Of course AArch64 is preferred, but hisi sdk also comes from ARM32 support for those chips.

Should we add those chips for ARM32?

yes, but it's not in high priority. for those boards with low memory this might make sense.

[185264646]

Hi3798 V200+ come from Cortex-A9. Of course AArch64 is preferred, but hisi sdk also comes from ARM32 support for those chips.

Should we add those chips for ARM32?

不太容易。阻力主要来自U-Boot。U-Boot的维护者不想支持64位U-Boot引导32位内核，反过来也是。搞不好要自己维护boot loader才有可能了。

支持ARM32是有一定好处的，因为ARM64过了ATF之后就变成non-secure状态了，据我测试non-secure状态下有很多硬件访问不了。寄存器读出来全是0.