fix(cpus): workaround for Cortex-X3 erratum 3692984

Cortex-X3 erratum 3692984 is a Cat B erratum that applies to
r0p0, r1p0, r1p1 and r1p2 and is still open.

The erratum can be avoided by disabling the
affected prefetcher setting CPUACTLR6_EL1[41].

SDEN Documentation:
https://developer.arm.com/documentation/SDEN-2055130/latest/

Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I054b47d33fd1ff7bde3ae12e8ee3d99e9203965f
3 files changed