fix(cpus): workaround for Cortex-A715 erratum 2420947

Cortex-A715 erratum 2420947 is a cat B erratum that applies only
to revision r1p0 and is fixed in r1p1. The workaround is to set
bit[33] of CPUACTLR2_EL1. This will prevent store and store-release
to merge inside the write buffer, and it is not expected to have
much performance impacts.

SDEN can be found here:
https://developer.arm.com/documentation/SDEN2148827/latest

Change-Id: I01a71b878cd958e742ff8357f8cdfbfc5625de47
Signed-off-by: Bipin Ravi <biprav01@u203721.austin.arm.com>
3 files changed