[AArch64] Workaround for cortex-a53 erratum 843419

[Marcus Shawcroft]

On 30 March 2015 at 15:23, Marcus Shawcroft <marcus.shawcroft@arm.com> wrote:
> Hi,
>
> Some early revisions of the Cortex-A53 have an erratum (843419).  The
> details of the erratum are quite complex and involve dynamic conditions.
> For the purposes of the workaround we have simplified the static conditions
> to an ADRP in the last two instructions of a 4KByte page, followed within
> four instructions by a load/store dependent on the ADRP.

Committed.

/Marcus