errata: workaround for Cortex A78 errata 1821534

Cortex A78 erratum 1821534 is a Cat B erratum present in r0p0 and
r1p0 of the A78 processor core, it is fixed in r1p1.

SDEN can be found here:
https://documentation-service.arm.com/static/603e3733492bde1625aa8780

Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: I71057c4b9625cd9edc1a06946b453cf16ae5ea2c
4 files changed