fix(errata): workaround for Cortex-A710 erratum 2136059

Cortex-A710 erratum 2136059 is a Cat B erratum that applies to
revisions r0p0, r1p0 and r2p0 of the CPU. It is fixed in r2p1.
The workaround is to set CPUACTLR5_EL1[44] to 1 which will cause
the CPP instruction to invalidate the hardware prefetcher state
trained from any EL.

SDEN can be found here:
https://developer.arm.com/documentation/SDEN1775101/latest



Signed-off-by: Bipin Ravi <bipin.ravi@arm.com>
Change-Id: I43a86a365418fb663cc1b6ab1d365b4beddae0bc