errata: workaround for Neoverse V1 errata 2139242

Neoverse V1 erratum 2139242 is a Cat B erratum present in the V1
processor core.  This issue is present in revisions r0p0, r1p0,
and r1p1, and it is still open.

SDEN can be found here:
https://documentation-service.arm.com/static/60d499080320e92fa40b4625

Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: I5c2e9beec72a64ac4131fb6dd76199821a934ebe
3 files changed