fix(errata): workaround for Neoverse-V1 erratum 1618635

Neoverse-V1 erratum 1618635 is a Cat B erratum that applies to
revision r0p0. It is fixed in r1p0.
The workaround is done through the instruction patching
mechanism, which is performed by a write sequence of
IMPLEMENTATION DEFINED registers.

SDEN can be found here:
https://developer.arm.com/documentation/SDEN1401781/latest/



Signed-off-by: Juan Pablo Conde <juanpablo.conde@arm.com>
Change-Id: I53e406735cd3a2a930fdc72ebce3bbed97100168