fix(errata): workaround for Cortex-A510 erratum 2347730

Cortex-A510 erratum 2347730 is a Cat B erratum that affects
revisions r0p0, r0p1, r0p2, r0p3, r1p0 and r1p1. It is
fixed in r1p2. The workaround is to set CPUACTLR_EL1[17]
to 1, which will disable specific microarchitectural clock
gating behaviour.

SDEN can be found here:
https://developer.arm.com/documentation/SDEN1873351/latest
https://developer.arm.com/documentation/SDEN1873361/latest



Signed-off-by: Akram Ahmad <Akram.Ahmad@arm.com>
Change-Id: I115386284c2d91bd61515142f971e2e72de43e68