[AArch64] Add feature flags and command line for ARMv8.2 FP16 support.

[Marcus Shawcroft]

On 25/11/15 01:49, Joseph Myers wrote:
> Out of interest, when will ARMv8.1 and v8.2 be documented in the ARM
> Architecture Reference Manual?
> <https://community.arm.com/groups/processors/blog/2014/12/02/the-armv8-a-architecture-and-its-ongoing-development>
> said "mid-2015" for v8.1, but as far as I can see DDI 0487A.h is current
> and doesn't seem to mention v8.1 anywhere obvious.
>

Hi Joseph,

It was hoped to publish an ARMv8.1 supplement by the end of the year, 
however, this will now be during the 1H-2016, and hopefully in Q1 of 
next year. The intent is to publish the ARMv8.2 details within 6 months 
of ARMv8.1.

Thanks
/Marcus